Why is NSXMLParser crashing for me on 10.5? (Mostly PowerPC, but some Intel.)

Question

I have some strange problems with crash reports from 10.5.

Thread 11 Crashed:
0   libxml2.2.dylib                 0x93753ec0 xmlClearParserCtxt + 1776
1   libxml2.2.dylib                 0x9372f724 xmlParseCharData + 308
2   libxml2.2.dylib                 0x93735034 xmlParseChunk + 3624
3   com.apple.Foundation            0x920c57c0 -[NSXMLParser parse] + 236
4   com.myDomain.MyApp              0x000978bc 0x1000 + 616636
5   com.myDomain.MyApp              0x0008867c 0x1000 + 554620
6   com.apple.Foundation            0x92092614 -[NSOperation start] + 620
7   com.apple.Foundation            0x92014d84 __NSThread__main__ + 1004
8   libSystem.B.dylib               0x903960d0 _pthread_start + 316

All the report's I get are from 10.5 machines and most of them are PPC's but not all. I tried a lot a things to reproduce this but without any success. Anyone else had this Problem? Found a solution for it?

//edit: added the header of the crashlog

Version:         2.0.4 (2.0.4)
Code Type:       PPC (Native)
Parent Process:  launchd [86]

Date/Time:       2010-10-12 20:26:12.145 -0400
OS Version:      Mac OS X 10.5.8 (9L30)
Report Version:  6
Anonymous UUID:  

Exception Type:  EXC_BAD_ACCESS (SIGBUS)
Exception Codes: KERN_PROTECTION_FAILURE at 0x0000000000000000
Crashed Thread:  11