Owing to resource limitations, we have had to remove the TESS website from service. The author of TESS left the group some time ago and we cannot provide support for it. That means we cannot answer questions about its usage.
However, the tessWms source code is available from the downloads section under TESS/. It is packaged with a README and a license as a zip file. The source code, tessWms.c, is in C and beyond a compiler has no dependencies. It does require providing PWMs (partial weight matrices). Freely available ones used by TESS are:
TRANSFAC 7.0 Public (2005) Database and
To install and run, please read the README.txt file. Please note that this is not software reproducing the TESS web site. That is not available.