Cryptic exception when the git folder can't be found

[asbjornu]

I accidentally had TeamCity's VCS checkout mode set to Automatically on server, which caused GitVersionTask to fail with a pretty cryptic exception:

[22:15:20] [UpdateAssemblyInfo] WriteVersionInfoToBuildLog
[22:15:20] [WriteVersionInfoToBuildLog] WARN [07/16/15 22:15:20:22] Could not determine assembly version: Value cannot be null.
Parameter name: path

Is it possible to make this a bit clearer?