You said that "Path to Perforce exe is set to C:\Program Files\Perforce\p4v.exe".
p4v.exe is the GUI tool for Perforce.
You probably want the command line tool for Perforce, which is 'p4.exe'.
See if you have 'p4.exe' in the same directory, and change your configuration to point to p4.exe instead of p4v.exe.