revGoURL "mailto:" bonks on Windows NT 5.1

[Sivakatirswami]

I have this in a script that works on most all machines including  
Windows

revGoURL ("mailto:katir at hindu.org?subject=" & tSubject & "&body=" &  
tBody)

But one Windows NT 5.1 user is telling me that she gets this message  
from their system:

" popup message says "The command line argument is not valid. Verify  
the switch you are using."

She says: "Probably my VERY STRONG firewall?"

Any insights?

Sivakatirswami