In short: the code you sent is broken - fix it. See figure.1
The original code was written by Bill Joy back in the 70s.
It has been tweeked and recompiled a number of times over the years
as changes in operating system caused the previous binary to
abend with a diagnostic.
But it is a bit spooky when a program just stops working for
no obvious reason. In the case of this particular program,
the breakage is easy to spot and a workaround devised.
We should always be so lucky.
--
Chuck Forsberg WA7KGX N2469R caf(a)omen.com
www.omen.com
Developer of Industrial ZMODEM(Tm) for Embedded Applications
Omen Technology Inc "The High Reliability Software"
10255 NW Old Cornelius Pass Portland OR 97231 503-614-0430