We are currently working on fixing this!
At this time we ask that after receiving this warning about any particular item you wait 1 hour, and then try again.
Why?
It looks like our Garbage Collection on our asset server may have hiccuped. While this isn't good and we will fix it, there is a contingency process in place. This process adds any items that can't be found to a queue to be restored. The restoration should happen within an hour of the first attempt to use the item.
Linden Answers is NOT, I reapeat NOT the right place to report this! For immediate issues like these please use Live Help (in the Help menu), and email or call support (more details at http://secondlife.com/community/support.php). We are aware of this issue, and as such I will be removing all related posts.
If your items are still missing after 1 hour please let us know -
[email=bugs@lindenlab.com]bugs@lindenlab.com[/email]
[email=support@lindenlab.com]support@lindenlab.com[/email]
Relevent information to include:
Your resident name
The sim you were in
The time you first got the message about missing from database
The last time you tried to access the item
The name of the item and the directory in your inventory for it.
If you can get it, the asset id of the item (right click on it in inventory, choose 'Copy Asset UUID' then paste into a text editor).
This information is specifically for items that have gone missing within the last 24 hours or so. (2006-11-09 to 2006-11-10).