XEmacs 21.4.2 Hung with Fatal IO Error

After using the same XEmacs session for days, I got this error when trying to have XEmacs display some contents with a new frame. The frame popped up fine, but XEmacs hung with the error below, showing partial contents: xemacs-21.4.2: Fatal I/O Error 0 (Error 0) on display connection ":0.0" after 964101 requests (964100 known processed) with 5 events remaining. Here's the stack trace: tonywl＠philly> /usr/proc/bin/pstack 14050 14050: xemacs-21.4.2 fed194c0 _poll (16, 0, ffbed230, ffbed1b0, ffbed130, ffbecfd0) + 8 fefbbcc0 _XtWaitForSomething (302400, 0, 0, 1, f4240, 0) + 1e4 fefc0e94 XtAppPending (4, 1, 2, 4, 302400, 1) + 264 0017bc3c drain_X_queue (2a761c, 12aa2, 12a81, ffbed4a0, 0, 0) + 2c 0017bd68 emacs_Xt_event_pending_p (1, 2a264c, 2d2804, 0, 0, 0) + 110 000b9558 event_stream_event_pending_p (1, 2d2804, 2d2804, 0, 0, 0) + 20 000ba174 detect_input_pending (2d2804, 187b064, 2d2804, 0, 0, 2a2400) + 4 000bb75c run_pre_idle_hook (2d2804, 2d2804, 2d2804, 1, 2d2804, 0) + 20 000bbb2c Fnext_event (2d2804, 2a264c, 552380, 0, 20da65c, 5ad600) + 3a0 0006bf6c Fcommand_loop_1 (2a2400, 1, 2a7c00, 0, 0, 0) + 194 00089594 condition_case_1 (296000, 2a2800, 2a1000, 6b77c, 2d2804, 0) + 110 0006b884 command_loop_3 (0, ffbed8e0, ffbed958, 0, 0, 0) + 40 0006b8b8 command_loop_2 (2d2804, 6b8b4, ffffffff, fffffff8, 0, 1d1d0ed) + 4 000891f4 internal_catch (2e60c4, 6b8b4, 2d2804, 0, 0, 0) + b0 0006bab0 initial_command_loop (2c80e8, 2a1000, 4d3fb0, 4d3f9c, 322234, 321810) + 1e0 000855a8 xemacs_21_4_2_sparc_sun_solaris2_7 (1, 2d2804, 2c8000, 2a0c00, 2c8400, ffbedbc4) + 10b8 00085e34 main (1, ffbedbc4, ffbedbcc, 285c00, 0, 0) + b8 00051cd4 _start (0, 0, 0, 0, 0, 0) + dc In XEmacs 21.4 (patch 2) "Developer-Friendly Unix APIs" [Lucid] (sparc-sun-solaris2.7) of Fri May 11 2001 on micasa configured using `configure --prefix=/import/dream/tools --with-prefix=no --package-path=/import/dream/tools/lib/xemacs/xemacs-packages --with-gcc=no '--cflags=-v -xO2' --with-x --with-xpm '--site-includes=/import/dream/tools/include /usr/dt/include' '--site-libraries=/usr/lib /import/dream/tools/lib /usr/dt/lib' --with-database=berkdb,dbm --with-png --with-jpeg --with-tooltalk --with-workshop --with-cde --with-sparcworks=yes --with-xface --with-socks=no --with-mule=no --with-xfs=no --error-checking=no --debug=yes --with-gtk=no' Tony