MHo 2014-03-25: Active Tcl 8.6.1 at home, 32 bit, no problem. Active Tcl 8.6.1 at work, 64 bit:

C:\Windows\system32>teacup update-self
Updating D:/home/Hoffmann/Programme/Tcl/bin/teacup.exe ...
Not found in the archive.

How can I update teacup.exe, then?