Tiger bug in NSXMLParser?

I'm using NSXMLParser to read an XML do***ent from a server via 
initiWithContentsOfURL. This works just fine under Leopard. I can read 
and parse the data just fine, but under Tiger, I get an empty do***ent 
error: NSXMLParserErrorDomain = 4 (Empty do***ent). There are several 
posts in the archives about problems with NSXMLParser, but nothing 
suggesting a Tiger bug leading to an empty do***ent. Unless someone 
thinks there's something wrong with my code, I'm going to file a bug 
with Apple.

Here is my code:
NSXMLParser* locationData = [[[XMLParser alloc] 
initWithContentsOfURL:[NSURL URLWithString:urlString]]  autorelease];
[locationData setDelegate:self];
[locationData parse];
NSError* err = [locationData parseError]; <---Empty do***ent error


urlString is an NSString that was created using 
stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding

The do***ents encoding is actually Latin1, I pasted the last one I tried 
here. I've tried a few encodings, but they all fail with the same error.
Any ideas?