Brian, thanks for responding. Yeah, I actually set up Splashtop the other day. So, now I can control the server from my laptop client when necessary. However, that wasn't really the problem I was having.
I eventually found the solution here:
https://yabb.jriver.com/interact/index.php?topic=99693.0I think my original description of the problem was inaccurate. I'll restate it, just for the sake of anyone else who might run into the same problem.
I have a laptop that is the library client of another PC, which is the server. I wanted to sync my handheld device (android phone), through the laptop client. I found that I could do this, but it took a LONG time, because the files were being converted from FLAC to MP3. So, I wanted to create MP3 versions of each song, so that the sync would be quicker. When I performed the sync, JRiver would create MP3 versions, and store them in the "Conversion Cache" folder, on the server PC. When I went to sync those same files to the handheld again, JRiver would look for MP3s in the conversion cache folder, and use them, as expected. Great! The problem was that I wanted to make MP3 versions of every song in my library (about 11000), and using the sync feature to create these MP3 versions didn't seem very efficient. I would have had to transfer all of my music to my handheld, just to perform the MP3 conversions. It isn't possible to perform file conversions on the server from the library client. This option is greyed out when you are looking at files from the client. The next thing I tried was to get on the server, and perform file conversions, with the destination folder being the conversion cache folder. However, when I then tried to sync the handheld from the library client, the files that were in the conversion cache folder were not used. The conversions were, instead, done again when syncing, and I ended up with duplicates.
The solution, which is mentioned in the post linked to above, was to create a "virtual handheld", which was a folder I made on my client desktop, and to perform a sync to that folder. This way, MP3s were stored in the server's conversion cache folder, and were remembered when I did the next sync.
I hope that makes sense to anyone having the same problem.