rds weird error - mac x - screenshot included

Hi, having weird peoblems connecting to our remote rds server, it seems to be asking for a weird directory - C/\/. -could this be anything to do with macs not liking : ? though i've had it working before on the same settings. is it possibly a firewall issue? my ip address is allowed to log on with no restrictions.

the setting is correct in the rds settings ie: C:\ or even c:\inetpub\wwwroot - has anyone encountered this before?

see a screenshot of the error message http://www.felixcorke.pwp.blueyonder.co.uk/error_0001.jpg

thanks for your help in advance

felix