Regardless of whether an input file may be broken, it must not crash
the decoder.

diff -Nur audacious-plugins-fedora-2.2-orig/src/adplug/core/lds.cxx audacious-plugins-fedora-2.2-adplug-lds/src/adplug/core/lds.cxx
--- audacious-plugins-fedora-2.2-orig/src/adplug/core/lds.cxx	2009-11-22 23:49:52.000000000 +0100
+++ audacious-plugins-fedora-2.2-adplug-lds/src/adplug/core/lds.cxx	2010-01-25 19:09:28.000000000 +0100
@@ -665,6 +665,9 @@
 void
 CldsPlayer::playsound (int inst_number, int channel_number, int tunehigh)
 {
+  if (inst_number > numpatch-1) {
+      return;
+  }
   Channel *c = &channel[channel_number];    // current channel
   SoundBank *i = &soundbank[inst_number];   // current instrument
   unsigned int regnum = op_table[channel_number];   // channel's OPL2 register