Index: trunk/tools/shorten-filenames.pl
===================================================================
--- trunk/tools/shorten-filenames.pl	(revision 1164)
+++ trunk/tools/shorten-filenames.pl	(revision 1171)
@@ -17,5 +17,5 @@
 		my $s = uc $e;
 		$s =~ y/-_//d;
-		my ($f, $x) = $s =~ /^([0-9A-Z]+)(\.[0-9A-Z]+)?$/ or die "$l: illegal filename\n";
+		my ($f, $x) = $s =~ /^([0-9A-Z]+)(\.[0-9A-Z]{1,3})?$/ or die "$l: illegal filename\n";
 		$f = substr($f, 0, $n);
 		my $c = 1;