Hi,
I've had a similar but opposite problem. I've been trying to load raster datasets into a raster catalog in ArcSDE and have been getting the same error. This happened before and just before calling tech support a light went off.
I resolved my issue by deploying the wizard/tool from one account, I suggest SDE Administrator but browsing to the data in another account.
For example, I have a raster catalog built in the SDE Admin account and right click, load data, and browse to the data under a different database connection, in my case I used a windows authenticated account.
I don't remember the rationale why this works but it works for me. It has something to do with the fact that ArcSDE can't load data into an object from the same account b/c the open object (the one receiving the data) more/less locks the account and by getting the data from the other account it can load it in.
Try it and I hope it works for you.
Hilary
Capital Regional District, Victoria, BC