Perforce error - not under client's root.

When checking in a file via UE4, I get an error that my path isn’t under the client’s root. Here is the part from the log file

LogSourceControl: Attempting 'p4 opened C:/Program Files/Unreal Engine/4.1/...'
[2014.04.25-22.08.38:376]  0]LogSourceControl: Attempting 'p4 client -o CalebSnow'
[2014.04.25-22.08.38:376]  0]LogLoad: Full Startup: 5.40 seconds (BP compile: 0.07 seconds)
[2014.04.25-22.08.38:388]  0]LogContentBrowser:Verbose: The content browser source was changed by the sources view to '/Game/Materials'
[2014.04.25-22.08.38:403]  0]SourceControl:Error: Error Path 'C:/Program Files/Unreal Engine/4.1/...' is not under client's root 'D:\CalebSnow'.

I want to know why it’s trying to look on my C: drive in the first place?

Another question: How can myself and my team reliably check out levels? I don’t see an easy way to do this in UE4 unless it’s through P4V.

Having the same issue at the moment, although my editor is installed on D: while the projects are on C: by default. There really is no reason at all why the the editor installed through the launcher should worry about not being under the clients root as it has nothing to do with my project and should certainly not be under source control.