why am I getting this message"Cannot create rquested inventory."

[Julianna Warrhol]

That sort of error is often a server issue.  Have you tried rezzing the item on a different sim?  Your sim might just need to be restarted. 

[Lucretia Brandenburg]

What Rolig said ... when that happens to me at multiple sims, I chalk it up to LL doing inventory maintenance on the sly or general SL wonkiness and relax - these issues don't last forever.

[Rolig Loon]

If you look at the Grid Status Blog for the past two weeks, you'll see that Linden Lab has had a half dozen inventory maintenance periods, some scheduled and many unscheduled.  The techies are obviously trying to fix something.  If we're lucky, there will be an upgrade in one of the next server rollouts.  The next time your sim gets an upgrade, check the release notes to see what bugs they have cleared and which ones remain.