Git package errors

I have a 2-boot machine between Windows 8 and Ubuntu 12.04.

The shared filesystem has a Git repository / workspace. It was built using msysgit from Windows.

When I try to use this repo on Linux (using Git 1.7.9.5) I see these error messages:

error: packfile.git / objects / pack / pack-31c385e8e4f1c105da16758ee98043a4b4ea1e50.pack signature not available

warning: batch file .git / objects / pack / pack-31c385e8e4f1c105da16758ee98043a4b4ea1e50.pack is not available

error: packfile.git / objects / pack / pack-31c385e8e4f1c105da16758ee98043a4b4ea1e50.pack signature not available

warning: batch file .git / objects / pack / pack-31c385e8e4f1c105da16758ee98043a4b4ea1e50.pack is not available

fatal: Could not read object 190cb002f6257e33efe88a91b37943be29cf9412: value too large for a particular data type

First, what does this mean?

Second, is this an indication that the contents of the folder are .git

distribution dependent, be it OS or git version / implementation?

I can get around this by making another clone of the repo, but I'd rather use the same one from both OSes if possible.