I want to use the GOMI recorder on CD on one PC and move the recorded file to another PC during market hours. Where is the recorded file stored?

It's in the directory where you pointed your environment variable to. If you didn't set this up, they should be being written to the \My Documents folder.

If you have not set up an environment variable to a dedicated folder (like C:\GomFolder), then your best bet is to do so. You can then share that directory across your network, and I think you can point the other (networked) PC's environment variable to that network resource (or map it via a drive, to make it look local to that PC), and (in theory) you can have that networked PC's NinjaTrader display/read any GOM chart changes from the "master" PC's C:\GomFolder - this way, you don't need to 'move' or copy the file to the other PC (Note, you still need to have the GOM framework on the "remote" PC - none of the indicators will be set to WRITE the binary file though.)