Cannot mount USB drive from remote Mac after installing network switch

[AVR2]

My previous home network setup was MBP into the single GbE port on my wireless router, a Mac mini into the 10/100 port. Both talked perfectly to each other.

The Mac mini has an external USB drive called Media 2, and I could use the MBP to access it.

Today I installed a GbE switch so that both Macs can talk to the GbE port on the router, and now I can't mount the Media 2 drive using the MBP.

I get this box every time:



I can connect to the Mac mini using screen sharing and access Media 2 that way. While I'm screen sharing the mini via the MBP, I can copy from Media 2 to the MBP. I just can't mount Media 2 directly on the MBP.

I've Googled around, and the most common solution - restart the Finder - hasn't worked.

Any suggestions gratefully received!

 

[AVR2]

OK, after a bit more investigation it seems to be a permissions issue, but I have no idea how to fix it.

If I use "Connect to Server", it asks me to select the volume I want to mount, and if I choose Media 2 it says "You do not have permission to access this server".

I can connect to all the other volumes in the list with no problems.