asterisk users - May 2005 - TDM04B and spandsp can't send a fax

TDM04B whit 4 FX0  modules
spandsp 2pre18 
AMD XP box 
asterisk@home

when i try to send a fax this fails on sender side in a middle of
transmition,  the receive side(* box) keep working 35 seconds on RxFax
command after sender hang up, and no tif file has generated.

in other post have a info about frame slips, but not how to resolve it.

How i can solve this poblem?

thanks 

David Romero
##################################