Thanks for the replies people - I will try changing the cables - didnt think of that one yet!

I got this back from the Access tech dept...

"Thank you for your mail. The settings on the Virus are correct and this error message simply says that data didn't arrive correctly in the Virus at all. It's hard to say what might be the problem. Either the data was already recorded wrong or the Midi interface scrambles the data when trying to send it back to the Virus.
The Atari ST was rock solid concering this - I know."

so I dont think its a Virus settings problem, more likely things have got a lot more complex since i moved in the G5 in place of my trusty ST...

I noticed this as well with my Mac. Maybe it's a Mac problem with the Virus? Maybe something similar to xml loading on images after photoshopping? Possibly something the mac does when you save to the HD? Just threw that out there.

One way to test is doing it with a PC.

Maybe a factory reset is in order before loading the patches?

I ran the giant patch bank from the ampfea.org site. It said the checksum error but the patches loaded anyway...

But I never had problems loading things to other synths.

I have had no troubles with MAC, but I am using the MOTU Microlite MIDI interface.

I think this is key in these situations.....you need a decent MIDI interface

I have just had this problem too, i thought it would be a good idea to do a dump tx into logic 6 so that i could use the virus in other arrangements. The dump seemed to transfer ok, i changed a setting on one of the midi channels, then tried restoring the dump into the virus as a test. The next thing i have a checksum error and all the patches dont play anymore, just getting a half note. i cannot believe it......

My gut reaction is that i have to reinstall the operating system in order to get the virus working again?