Open Folder Options from the Control Panel. Click the [File Types] tab and
scroll down to the TSV entry. Click the [Advanced] button. For each action
listed, highlight to select it and then click [Edit] to edit it. Scroll to
the end of the "Application used to perform action" field and place
double-quote (") marks around %1 at the end of the entry.

I still don't understand why some workstations can open TSV files without
this modification and some cannot (all running XP Pro,sp3 and MSO2003sp3);
but the solution worked for me.