forum user shorshe sent me the following:

File:   /SourceCache/DevToolsBase/DevToolsBase-515/pbxcore/Target.subproj/PBXBuildSettingsDictionary.m 
Line: 111
Function: PBXBuildSettingsDictionary_getValueForKeyPath

value should be a string, but it is <NSCFArray:0x03a69c80>

Couldn't open /Users/[deleted]/Desktop/adium-0.82/Adium.xcodeproj/Adium.xcode.

Reason: *** -[NSCFArray length]: selector not recognized [self = 0x3a69c80].


Uncaught Exception:
*** -[NSCFArray length]: selector not recognized [self = 0x3a69c80]

Stack Backtrace:
The stack backtrace has been logged to the console.

looks like that array in the build settings was an issue after all. I wonder, though, if it wouldn't still be trivial to write an Xcode 2.0↔2.1 translator. thanks, shorshe.