i experienced this matter the 2nd time. The last time(yesterday) occured after installing OP enhancement patch v5.
I said: Well, probably it's the same as the 2500 to 2552 patch; it must be installed on a fresh install of OP.
Ok i did that: Chose options, installed OP v2500, applied, 2500 to 2552, installed D2 scripts, DLL's, ezINI , bonus missions, CoOP and i have put my versions of Shiplist, ftrlist, and strings .
Now, i don't know because of what mentioned above the game is not playable.
By not playable i mean: start OP, intro video (OK) , OP splash screen , because it's a fresh copy it required the key which was entered correctly, and after the key is inserted, i wait a minute "admiring the splash screen" and suddenly the screen blanks, and i get the message: StarFleetOP has encountered an error and needs to close.
Not to mention the minor modifications to the gorn starbase images, changed mouse cursors with the ones in SFC1, and modifiyng ftrlist.