Runtime error for Release build app in XCode 4-Collection of common programming errors

I’m having some issues with running a app in Release build in Xcode 4. I get a run-time error on a message send to a Category method:

[NSCFString JSONValue]: unrecognized selector sent to instance 0x923600

I guess the category for some reason is not found correctly. There is no warnings, and this only happens in Release builds. The JSON Category is located in a static lib, linked to the main app. The project configuration still contains the -all_load flag.

EDIT:

This is the offending code:

    NSString *rawJson = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] ;
    NSDictionary *dataDic =[rawJson JSONValue];

the rawJson contains a valid string, and everything is working perfectly fine in debug builds

Any suggestions?

Thanx!