Sitemap errors in Webmaster Tools

[lapiervb]

I have two forums that show the following error in WMT:

Missing XML tag

This required tag is missing. Please add it and resubmit.

Any suggestions would be appreciated.

[ForceHSS]

<a href="https://vborg.vbsupport.ru/showpost.php?p=2489350&postcount=3" target="_blank">https://vborg.vbsupport.ru/showp...50&postcount=3</a>