Incorrect "Last Modified Date" for forumdisplay

[amc]

I am trying to create a google sitemap and I get the last modified date for certain forums as 1969:

<loc>http://www.domain.com/forumdisplay.php?f=12</loc>
<lastmod>1969-12-31T19:00:00Z</lastmod>
<changefreq>daily</changefreq>
<priority>0.8</priority>

Whereas other forums seem to be okay:

loc>http://www.domain.com/forumdisplay.php?f=17</loc>
<lastmod>2005-07-06T06:21:43Z</lastmod>
<changefreq>daily</changefreq>
<priority>0.8</priority>

Is there anyway I can correct this??

Thanks.

[Jake Bunce]

Dec 31, 1969 is timestamp 0.

What is this for? Where is the code coming from? Is it a custom script?

[amc]

Well this is for a google sitemap (https://www.google.com/webmasters/sitemaps/docs/en/about.html)

The code for this script is from http://www.vbulletin.org/forum/showthread.php?t=91389

[Jake Bunce]

You should ask T2DMan, the author of the plugin.