X applications crashing under 5.3BETA7 and X.org

[freebsd-stable at auscert.org.au]

I have a problem with applications crashing. Xterm will launch and run ok,
but any attempt to mouse select text will cause an immediate crash with
this output on the console:

xterm:  warning, error event received:
X Error of failed request:  BadAtom (invalid Atom parameter)
  Major opcode of failed request:  18 (X_ChangeProperty)
  Atom id in failed request:  0x17f
  Serial number of failed request:  131
  Current serial number in output stream:  133

If I attempt to run a gui app like wish, it won't launch and produces this
error:

  %wish8.4
X Error of failed request:  BadAtom (invalid Atom parameter)
  Major opcode of failed request:  18 (X_ChangeProperty)
  Atom id in failed request:  0x1a5
  Serial number of failed request:  12
  Current serial number in output stream:  15

I'm running 5.3 on the server and desktop, with X forwarded over an ssh
tunnel. I don't experience this issue when performing the same operation
but with a Microsoft Windows/XWin32 desktop. Is this an issue with the
X.org Xserver on the 5.3 workstation? Let me know what other detail I can
provide if needed.

cheers,
joel