And here is another good one to look into on this problem. The enwiki-20070206 imports FAIL with reports of "NULL title detected" when running importDump.php from 1.8.2. The problem is, there are NO NULL titles contained in this XML file.
I have a tool that strips out the titles from the dumps for translation and link grammar parsing. These tools do not affect or alter the enwiki xml file at all but simply READ FROM IT, I just use them to strip out the article titles.
Here is the output for the enwiki dump when article titles have been striped and redirected to a file. There is not a single NULL title or revision in the entire XMl Dump. This SAME UNMODIFIED DUMP FROM THE FOUNDATION crashes in importDump complaining of NULL titles when THERE ARE NO NULL TITLES IN THE DUMP AT ALL.
Stripped Titles enwiki-20070206:
ftp://www.wikigadugi.org/wiki/xml/titles-enwiki-20070206.txt.bz2
importDump.php Logs with crash and BOGUS NULL title error importing enwiki-20070206:
ftp://www.wikigadugi.org/wiki/xml/log-enwiki-20070206.txt.bz2
Jeff