[ns] can't read "ns" : no such variable

["Nino.Kubinidze" <Nino.Kubinidze@ul.ie>]

Hello,
I use ns-allinone-version 2.1b7a, on Solaris CDE 1.3 platform.
The problem I face is the following:
when I run scripts from ns-2.1b7a/tcl/ex I get the message

% can't read "ns" : no such variable

in many copies. 
This appears in Run after   $ns run.

I can run the only simple script from Marc Greis's page, section IV.2.
(transmission of packets from node0 to node1).
Can anybody tell me, how to run all the scripts from ns-2.1b7a/tcl/ex or
/tcl/test without problems?
Thanks in advance.

Nino Kubinidze