Program stalls, Sitemap has mostly blank entries & generates errors

[phil6]

I am having 3 problems with the program. 
1. The crawling usually dies out.  It will not complete an entire sitemap without being restarted many, many times.  I have cron jobs for a few sites, but sometimes it still doesn't work.  Any suggestions?

2. My main site has a sitemap of about 40,000 pages.  When I looked through it I see a lot of blank entries like this:
<url>
<loc/>
<priority>0.50</priority>
<changefreq>daily</changefreq>
<lastmod>2010-02-23T17:41:44+00:00</lastmod>
</url>

3.  When the crawling completed for the above site, I got these  error messages:
Warning: ksort() expects parameter 1 to be array, null given in /home/domain/public_html/generator/pages/class.html-creator.inc.php on line 58

Warning: Invalid argument supplied for foreach() in /home/domain/public_html/generator/pages/class.html-creator.inc.php on line 60

Any suggestions?
Thanks,
Phil

[XML-Sitemaps Support]

Hello,

1. it looks like your server configuration doesn't allow to run the script long enough to create full sitemap. Please try to increase memory_limit and max_execution_time settings in php configuration at your host (php.ini file) or contact hosting support regarding this.

2, 3. if you have "use temporary files" enabled, try to disable it as it may fail on larger sites.