Undocumneted I/O Error?

[Kiran C]

Hi all,
I am trying to use Generic Coverage Tool (GCT) to do code coverage  analysis
of my c code.
GCT initially pre-proccesses the c code , instrumenting it..
and then passes it on to gcc.
It works fine when my code does not conatin any #include statements.
But when my code contains say a #include<stdio.h>
I get the follwing error
=============================
$ make CC=gct
gct    -c -o lc.o lc.c
In file included from lc.c:8:
/usr/include/stdio.h:37: stddef.h: undocumented I/O error
/usr/include/stdio.h:40: stdarg.h: undocumented I/O error
In file included from /usr/include/sys/reent.h:14, from
/usr/include/stdio.h:48, from lc.c:8:
/usr/include/time.h:30: stddef.h: undocumented I/O error
In file included from /usr/include/time.h:32, from
/usr/include/sys/reent.h:14, from /usr/include/stdio.h:48, from lc.c:8:
/usr/include/sys/types.h:31: stddef.h: undocumented I/O error
gct    -c -o get.o get.c
In file included from get.c:5:
/usr/include/stdio.h:37: stddef.h: undocumented I/O error
/usr/include/stdio.h:40: stdarg.h: undocumented I/O error
In file included from /usr/include/sys/reent.h:14, from
/usr/include/stdio.h:48, from get.c:5:
/usr/include/time.h:30: stddef.h: undocumented I/O error
In file included from /usr/include/time.h:32, from
/usr/include/sys/reent.h:14, from /usr/include/stdio.h:48, from get.c:5:
/usr/include/sys/types.h:31: stddef.h: undocumented I/O error
gct -o lc lc.o get.o
gct.exec: cannot open lc.o
gct.exec: cannot open get.o
gct.exec: No input files specified.
==================================
What could be the cause for this problem?
code works fine when I use just gcc it compiles fine?
What does un documented I/O error mean?
I am using GCT 2.0B on Cygwin
(http://www.doc.ic.ac.uk/~pd200/SunSite/Mirrors/cs.uiuc.edu/pub/testing/)
My Cygwin gcc is gcc version 2.95.3-5 (cygwin special)
Thanks,
Kiran