Need help with error "vmError: VmTableData Sef Alias in record is missing! ...

[designsite]

Could someone please help me with this error "vmError: VmTableData Sef Alias in record is missing! Can't save the record with no Sef Alias." when i try to add a category for the products in virtuemart.
It worked once then never again. The only thing I can think of that might have affected it was I deleted some other unescessay users in backend?
joomla 2.5
virtuemat 2.6.10

[jenkinhill]

? http://forum.virtuemart.net/index.php?topic=123917.