Tilman is probably proposing the right solution here. However, you should know that it looks like your sources are old. Try invoking:
cvs status packages/acs-tcl/tcl/apm-xml-procs.tcl
If you are on 4-6 you should be on version 1.11.2.4. Don provided a workaround for old nsxml modules in version 1.11.2.2 and I merged that workaround over to head today as I had this very same problem.
