This connection looks like a windows share which is blocked by most ISPs since it's too dangerous for many reasons (I won't duplicate why.)

-> What our office uses is a very small server that serves up content via OpenSSH (see google.com) We think it's nearly bulletproof and only need to open port 22 to said server. It's been running for years and has done well for us.

http://www.2brightsparks.com/bb/viewtopic.php?t=1640& may be useful if you absolutely must use a drive letter and mapping.

Bob