In QDataTypes.h update the "typedef struct" definitions from C by using new Objective-C methods, because they cause a Memory Allocation issue when trying ot open a "WAD"-file (textures) within the ToeTap.

Example call can be found in "TWADReader.m" at the line TWADReader.m#L107

SWAPINT32( WADEntries[e].filepos );

Eventually valuable inputs can be found in the following Stackoverflow discussion:
http://stackoverflow.com/questions/18822858/objective-c-cocoa-equivalent-of-fread

When Running ToeTag an creating a "New" file, the App crashes with the following exception:

ToeTag(10384,0x102ee1000) malloc: auto malloc[10384]: error: GC operation on unregistered thread. Thread registered implicitly. Break on auto_zone_thread_registration_error() to debug.

Occuring at the following line of TCMPReader.m:

ECRC->model = [reader loadMDL:tocentry->PAKFilename Offset:tocentry->offset Size:tocentry->sz];

Maybe this Stackoverflow thread gives some help on the issue:
http://stackoverflow.com/questions/5850141/seek-help-error-gc-operation-on-unregistered-thread-thread-registered-implic

The .nib Controller Views are still set for OS X 10.5 compatibility. They should be adjusted for OS X 10.9 compatibility, in terms of getting the Mavericks version up and running.