Whfc: No valid file spooled

[Dani Pardo <dani@minerva.enpl.es>]

 Hi, I'm using whfc in a couple of Win95 /NT as clients for HylaFax, and
I've noticed that sometimes, when I send something to print, the phone
dialog doesn't appear, and the message: 

 No valid file c:\tmp\faxspool spooled

 It happens specially when using M$-Word, and seems to happen more often
in slow computer than in faster ones.
 I guess it's something about the printer configuration in Windows, but I
already have the option "Wait until last page has been sent" and
configured the Postscript to "optimize for portability"..