Thanks for posting the list of modifications.  I brought them in as noted below:

These were already done in groupcoin or bitcoin-qt.

1.already in groupcoin   modify listen port 51333
2.already in groupcoin   sendto port 51333 ; I had to modify this to prevent from connecting to other running bitcoin that I and others  would be running
4.already in groupcoin   add rpcport=51332 to config or change as default
5.already in groupcoin   modify inflation settings but low priority since they won't be changing for years

12.already in bitcoin-qt   modify irc_address=irc.lfnet.org

These were not done and I changed them in groupcoin.

3.modify AddressVerson=244  ; or to another address header number from 0 - 255 so that you can't send to the wrong version of bitcoin or testnet.  I had hoped to add human readable headers to my addresses at some point like weeds_  beer_

Changed in base58.h:
#define ADDRESSVERSION   ((unsigned char)(fTestNet ? 244 : 245))


6.modify pszTimestamp="New York Times 1/Jul/11 page 1, U.S. Will Widen 2 C.I.A. Inquiries Into Jail Deaths"  or other you might have chosen

Changed in main.cpp:
const char* pszTimestamp = "New York Times 1/Jul/11 page 1, U.S. Will Widen 2 C.I.A. Inquiries Into Jail Deaths";


7.modify block_hashMerkleRoot=0xd597477ef4dac6078bebd0240be7da16556ba881f047823791ddc83676d16fde  or other you might have chosen

Note, I could not define block.hashMerkleRoot because it is built in main.cpp, I could only change the assertion.
Changed in main.cpp:
assert(block.hashMerkleRoot == uint256("0xd597477ef4dac6078bebd0240be7da16556ba881f047823791ddc83676d16fde"));

8.modify genesisblock=0x00000004d621bf2f4e8209d56371b456a0181018f9416142c7a7f8a0b6f976fa

Changed in main.cpp:
uint256 hashGenesisBlock("0x00000004d621bf2f4e8209d56371b456a0181018f9416142c7a7f8a0b6f976fa");

9.modify block_nTime=1309517065

Changed in main.cpp:
block.nTime    = 1309517065;

10.modify block_nNonce=1109660235

Changed in main.cpp:
block.nNonce   = 1109660235;

11.modify irc_channel=groupcoin

Changed in irc.cpp:
if (fTestNet) {
    Send(hSocket, "JOIN #groupcoinTEST\r");
    Send(hSocket, "WHO #groupcoinTEST\r");
} else {
    // randomly join #groupcoin00-#groupcoin99
    int channel_number = GetRandInt(100);
    Send(hSocket, strprintf("JOIN #groupcoin%02d\r", channel_number).c_str());
    Send(hSocket, strprintf("WHO #groupcoin%02d\r", channel_number).c_str());
}


After I made the changes and tried to run it, I got the following runtime error:

bitcoin-qt: src/main.cpp:2022: bool LoadBlockIndex(bool): Assertion `block.hashMerkleRoot == uint256("0xd597477ef4dac6078bebd0240be7da16556ba881f047823791ddc83676d16fde")' failed.


Could you please try to run groupcoin with the changes mentioned above for the genesis block in order to reproduce the error?