Look Up Columns Keep disappearing? Access 2007

[Amazingmin]

Hello,
It's me again, the Access new-boy experiencing more problems.......!
I have a datasheet, into which I created some look up columns and they were working fine, then the look up values disappeared. I recreated the columns, But they keep defaulting back to ordinary columns after you have selected them once. It happens with both single and multiple value options.
Can anyone offer a solution for this please?

Regards,........Amazingmin

[June7]

I have no idea what is happening. If you want to provide db for analysis, follow instructions at bottom of my post.