xterm - keys stop working

I am having a rather odd problem (or two related problems) using xterm on my new machine (Intel I7). I have OpenSUSE 12.2 X86_64 installed on this machine. It is connected to the same display & keyboard as my other machine, with a KVM switch (Belkin Flip). That machine runs an older version, 10.2 IIRC, and has no problems. I use FVWM2 as the window manager on both machines.

I work in xterms, running my editor (THE) in them. Many of the editing functions depend on key combinations: for instance, PgUp moves up one page, Ctrl-PgUp goes to the top of the file. These all work on the older machine (been using essentially the same setup for at least a decade on various Linux versions). On the new machine

  1. Some things just don’t work at all. For instance, Alt-~ is linked to a macro that runs make on the current code base, but on the new machine the editor never gets a key combination sent to it.

  2. Many other combinations work when I first boot the machine, but stop working after I use the KVM switch to flip to the older machine and back. For instance, the Ctrl-PgUp is received on boot, but after a flip pressing the same keys just reports a plain PgUP. (Oddly enough, if I do a remote login with “ssh -X -l” from old machine to new, I still have problem #1, but not #2: the remote shell still transmits the Ctrl-PgUp.)

I’ve no idea where to look for information on this. From searching, I found that X has apparently completely changed the keyboard driver model, but what little documentation I’ve found doesn’t seem to have anything relevant to my problems. Any suggestions?