Sounds like some drive letters have been included in scripts or texture calls.
What does the Guru-Game.log file list out as path names for the entries listed from the standalone build?
Also you can check the contents.txt file to see if there is a clue there.
Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 2400 Mhz, 4 Core(s), 4 Logical Processor(s), 8gb RAM, Nvidia gtx660, Windows 7 Pro 64bit, Screen resolution 1680 x 1050.