[ns] Problem with NIST package

[sofia insat]

hi,

I have to install the nist mobility package to implement vertical handover between Wimax and Umts
I have dowloaded nist package from http://w3.antd.nist.gov/cgi-bin/req_mobility.pl
but when i excecute ./configure i obtain this message:
Please correct the problem by telling configure where tclcl is
using the argument --with-tclcl=/path/to/package,
or the package is not required, disable it with --with-tclcl=no.

how can i resolve this problem and where can i dowload tclcl package and install it.

Thank you in advance for your help