Sitemap generation results in error

When generating the sitemaps on my big board, I am getting a blank page for quite a while and then this end result:

[SECTION START] tags [6,771.8Kb mem used] [148s (+138s)]
[create sitemap file] filename: sitemap_tags_1.xml.gz, number of urls: 20000 [8,981.8Kb mem used] [541s (+393s)]
[create sitemap file] filename: sitemap_tags_2.xml.gz, number of urls: 2141 [7,089.8Kb mem used] [557s (+16s)]
[SECTION START] blogs [6,773.2Kb mem used] [557s (+0s)]
[SECTION START] blog tags [7,204.0Kb mem used] [557s (+0s)]
[create sitemap file] filename: sitemap_blog_1.xml.gz, number of urls: 802 [7,345.6Kb mem used] [557s (+0s)]
[SECTION START] groups [6,774.5Kb mem used] [557s (+0s)]
[create sitemap file] filename: sitemap_group_1.xml.gz, number of urls: 2123 [7,079.9Kb mem used] [558s (+1s)]
[addon module] vbseo_sm_vba.php [6,775.4Kb mem used] [558s (+0s)]

Warning: fread() [function.fread]: Length parameter must be greater than 0 in /public_html/forum/vbseo_sitemap/vbseo_sitemap_functions.php on line 1800
[create sitemap file] filename: sitemap_addon_1.xml.gz, number of urls: 7 [6,883.6Kb mem used] [559s (+0s)]
[create sitemap index] filename: sitemap_index.xml.gz, number of sitemaps: 9 [6,884.9Kb mem used] [559s (+0s)]
Sitemap has been created. Click here to return [6,879.5Kb mem used] [572s (+14s)]


I have just updated to the latest file on here ( I was running 3.0 pl1 without such issues, but updated because I saw that the version in the downloads section here was recently updated.)
There should be about 100.000 threads in my sitemaps.

It looks like you have an error with your vba module add on.

Are your forums open for guest visits?

Not all forums are open to guests, but that would leave 100.000 threads to be included in the sitemap. That is how many threads were in the sitemap last week.

And you do have the 'include thread' option turned on in the sitemap tool?

Yes. Interesting enough the sitemap is generated well by cron, but not if generated manually by clicking the 'run generator' function.
So at least I have a working sitemap again. But the 'run generator' function has an issue.

Can you open a ticket with login details for further troubleshooting?