tkdiff error on Linux Redhat 5.5

tkdiff error on Linux Redhat 5.5

I installed tkdiff as root, and it runs fine under that user, but when I
switch to a local user I get the error:
Application initialization failed: Can't find a usable init.tcl in the
following directories:
/usr/local/lib/tcl8.0
/pune/tools/synopsys/vera/2009.12-6/vera_vD-2009.12-6_linux/lib/tcl8.0
/pune/tools/synopsys/vera/2009.12-6/tcl8.0/library
/pune/tools/synopsys/vera/2009.12-6/vera_vD-2009.12-6_linux/library
This probably means that Tcl wasn't installed properly.
Error in startup script: can't find package Tk 8.0
while executing
"package require Tk 8.0"
(file "./tkdiff" line 32)
How do I fix this?