What I have done so far:

• Generated new Genesis Block
• Generated new MerkleRoot
• Updated MerkleRoot
• Updated Genesis block values
• Commented out these lines
• Compiled on CentOS 6
• Created altcoin.confwith

rpcuser=someuser
rpcpassword=somepassword

• lauched ./altcoin

at this point all seemed to be OK but...

• ./altcoind getinfo

shows:

{
    "version" : 60300,
    "protocolversion" : 60001,
    "walletversion" : 60000,
    "balance" : 0,
    "blocks" : 0,
    "connections" : 1,
    "proxy" : "",
    "difficulty" : 1.00000000,
    "testnet" : false,
    "keypoololdest" : 1400530204,
    "keypoolsize" : 104,
    "paytxfee" : 0.00000000,
    "mininput" : 0.00010000,
    "errors" : ""
}

• so I try to use internal miner to mine first block ./altcoind setgenerate true 8
• while checking progress by ./altcoind getmininginfo i got strange output

which shows:

{
    "blocks" : 0,
    "currentblocksize" : 0,
    "currentblocktx" : 0,
    "difficulty" : 1.00000000,
    "errors" : "",
    "generate" : true,
    "genproclimit" : 4,
    "hashespersec" : 0,
    "networkhashps" : 1.46543,
    "pooledtx" : 0,
    "testnet" : false
}

At this point, I've issues ./altcoind stop and when I try to launch it again, debug.log shows:

Altcoin Network: genesis=0x00000000324a1b505ecd nBitsLimit=0x1d00ffff nBitsInitial=0x1c00ffff nStakeMinAge=604800 nCoinbaseMaturity=500 nModifierInterval=21600
ERROR: CTxDB::LoadBlockIndex() : Failed stake modifier checkpoint height=0, modifier=0x0000000000000000
 block index               1ms
Loading wallet...
nFileVersion = 60300
Error loading blkindex.dat
 wallet                  301ms
Done loading
mapBlockIndex.size() = 1
nBestHeight = -1
setKeyPool.size() = 101
mapWallet.size() = 0
mapAddressBook.size() = 1

• uncommented these lines
• lauched ./altcoind

and the same error over and over again... I am cracking my head already a while....

can one, please point me the right direction. thanks

UPDATE1:

• deleted all the content from ~/.altcoin/ except altcoin.conf
• launched ./altcoind
• issued ./altcoind setgenerate true 4

at this point I figured out ./altcoind starts up without complaining about stake modifier though everytime I want to restart I have to delete the contents of ~/.altcoin/ otherwise error pops up.

output of debug.log:

AltCoin version v0.5.4.0-unk-beta ()
Default data directory /root/.thecoin
Loading addresses...
dbenv.open LogDir=/root/.altcoin/database ErrorFile=/root/.altcoin/db.log
Loaded 0 addresses
 addresses                30ms
Loading block index...
AltCoin Network: genesis=0x00000000324a1b505ecd nBitsLimit=0x1d00ffff nBitsInitial=0x1c00ffff nStakeMinAge=604800 nCoinbaseMaturity=500     nModifierInterval=21600
00000000324a1b505ecd77b793658f4fa6cd386653fdabd7d1c66907177174d6
00000000324a1b505ecd77b793658f4fa6cd386653fdabd7d1c66907177174d6
d8098e7eb449eed16c09fd7c97dec2acd1ec386ced36cf970a05c92fc2c0a05b
CBlock(hash=00000000324a1b505ecd, ver=1, hashPrevBlock=00000000000000000000, hashMerkleRoot=d8098e7eb4, nTime=1508926967, nBits=1d00ffff, nNonce=2600258680, vtx=1, vchBlockSig=)
  Coinbase(hash=d8098e7eb4, nTime=1508926967, ver=1, vin.size=1, vout.size=1, nLockTime=0)
    CTxIn(COutPoint(0000000000, -1), coinbase 04ffff001d020f274c4c205468652045636f6e6f6d697374202d2054686520626f79636f7474206f662051617461722069732068757274696e672069747320656e666f7263657273202d204f63742031392032303137)
    CTxOut(empty)
  vMerkleTree: d8098e7eb4
SetBestChain: new best=00000000324a1b505ecd  height=0  trust=1  moneysupply=0.00
 Upgrade Info: v0.5+ txdb initialization
ResetSyncCheckpoint: pending for sync-checkpoint ab0dad4b10d2370f009ed6df6effca1ba42f01d5070d6b30afeedf6463fbe7a2
ResetSyncCheckpoint: sync-checkpoint reset to 00000000324a1b505ecd77b793658f4fa6cd386653fdabd7d1c66907177174d6
 Upgrade Info: no txdb upgrade v0.3->v0.4 detected.
 Upgrade Info: v0.5+ no txdb upgrade detected.
 block index               4ms
Loading wallet...
nFileVersion = 60300
Performing wallet upgrade to 60000
keypool added key 1, size=1
keypool added key 2, size=2
keypool added key 3, size=3
...
...
keypool added key 101, size=101
keypool reserve 1
keypool keep 1
 wallet                  755ms
Done loading
mapBlockIndex.size() = 1
nBestHeight = 0
setKeyPool.size() = 100
mapWallet.size() = 0
mapAddressBook.size() = 1
Bound to port 11111
Added 1.1.1.90:11111 from 127.0.0.1: 0 tried, 1 new
Added 1.1.1.1:11111 from 127.0.0.1: 0 tried, 2 new
ThreadRPCServer started
ipv4 venet0: 127.0.0.1
ipv4 venet0:0: 2.2.2.62
addrLocalHost = 2.2.2.62:11111
IRC seeding/communication disabled
ThreadSocketHandler started
ThreadOpenAddedConnections started
trying connection 1.1.1.90:11111 lastseen=-391515.5hrs
ThreadOpenConnections started
ThreadMessageHandler started
ThreadStakeMinter started
CPUMiner started for proof-of-stake
ThreadDNSAddressSeed started
Loading addresses from DNS seeds (could take a while)
Added 9 addresses from 0:0:0:0:0:0:0:0: 0 tried, 11 new
connected 1.1.1.90:11111
Added time data, samples 2, offset +0 (+0 minutes)
Moving 1.1.1.90:11111 to tried
version message: version 60006, blocks=0
getblocks -1 to 00000000000000000000 limit 500
trying connection 1.1.1.9:11111 lastseen=-391515.5hrs
Added 13 addresses from 1.1.1.90: 1 tried, 23 new
GetMyExternalIP() received [2.2.2.62] 2.2.2.62:0
GetMyExternalIP() returned 2.2.2.62
connected 198.143.186.9:11111
Added 21 addresses from 0:0:0:0:0:0:0:0: 1 tried, 44 new
...
...
2017-10-31 13:15:58 UTC Flushing wallet.dat    
...
4 processors
Starting 4 BitcoinMiner threads
CPUMiner started for proof-of-work
CPUMiner started for proof-of-work
CPUMiner started for proof-of-work
CPUMiner started for proof-of-work
...
...
ThreadRPCServer method=getmininginfo

despite it is up and running and both nodes are connected to eachother, outputs of ./altcoind getinfo and ./altcoind getmininginfo are still the same.

UPDATE 2

• removed all hard checkpoints from kernel.cpp link

• added ( 0, 0x0000000000000000 )

  // Hard checkpoints of stake modifiers to ensure they are deterministic static std::map<int, unsigned int> mapStakeModifierCheckpoints = boost::assign::map_list_of ( 0, 0x0000000000000000 ) // ( 0, 0x0e00670bu ) // ( 19080, 0xad4e4d29u ) // ( 30583, 0xdc7bf136u ) // ( 99999, 0xf555cfd2u ) // (219999, 0x91b7444du ) ;

• recompiled

• removed all the contents of ~/.altcoin/ folder

• added altcoin.conf

• launched ./altcoind

• issued ./altcoind getinfo - output is still the same

• issues ./altcoind setgenerate true 4 -

• debug.log output is the same as previously

• issued ./altcoind stop

• launched ./altcoind

at this point I it failed again with the same error message

AltCoin Network: genesis=0x00000000324a1b505ecd nBitsLimit=0x1d00ffff nBitsInitial=0x1c00ffff nStakeMinAge=604800 nCoinbaseMaturity=500 nModifierInterval=21600
ERROR: CTxDB::LoadBlockIndex() : Failed stake modifier checkpoint height=0, modifier=0x0000000000000000