John Gardeniers wrote in a message to All:

 JG>     My setup consists of BNU v1.70, Binkley v2.60 and a 2400 V42bis
 JG> modem. I've tried setting the buffers in BNU to just about any
 JG> size/combination you can imagine, all without any difference to
 JG> Zedzap transfers. The I have  no trouble using the same setup, with
 JG> Bink in terminal mode, to transfer files using normal Zmodem. 

What TSR programs are you running? Disk cache? Network? Are you running
Desqview or some other 'tasker?

Try taking everything out of the config.sys and autoexec.bat that you don't
absolutely need, and see if that clears the problem. 

--- timEd 1.10+