Unable to open/edit downloaded programs

I have a Series 2 DVR hooked up to our house network via wire.

I had been downloading saved sewing and other craft shows, trimming commercials, and moving to a portable hard drive hooked up to a ROKU on the TV my wife watches.

Six months ago, I started being unable to do anything with the downloaded shows. We can still watch them on the Tivo, but once I download them, the recordings give a "Windows Media Player encountered a problem while playing the file" error when I click the listing in Tivo desktop (version 2.7).

VideoReDo (Suite 4, version 4.21) gives me a similar error and tells me to check my MAK. I have and it's correct.

When I "pick recordings to transfer" in Tivo Desktop, it says there are no DVRs on my network. However, I can download using my browser and the IP address. If I download using my browser or kmttg and then copy the file/program to the Tivo Desktop directory, I get a "Windows Media Player encountered..." error when I try to watch.

Any recommendations? Please tell me it's something "easy."

Thanks,
John