Dyld Library not loaded / No suitable Image found / unknown file type

Question

I'm getting the following problem when sending an .app to a tester:

Dyld Error Message:  
  Library not loaded: @executable_path/../Frameworks/RegexKit.framework/Versions/A/RegexKit  
  Referenced from: /Applications/SP.app/Contents/MacOS/SP
  Reason: no suitable image found.  Did find:  
/Applications/SP.app/Contents/MacOS/../Frameworks/RegexKit.framework/Versions    /A/RegexKit: unknown file type, first eight bytes: 0x56 0x65 0x72 0x73 0x69 0x6F 0x6E 0x73  
/Applications/SP.app/Contents/MacOS/../Frameworks/RegexKit.framework/Versions/A/RegexKit: unknown file type, first eight bytes: 0x56 0x65 0x72 0x73 0x69 0x6F 0x6E 0x73

He's running Snow Leopard. It runs fine on my mac mini which is running 10.5.

I've tried rebuilding (including deleting project files and build directory) to no avail.