I have not yet solved this issue and still having the same issue. Is there a different way I can get my raster images in my geodatabase?
You can use the Copy Raster tool but what you are doing should work. Can you tell what happens if you disable the Background Processing option, and what version of ArcGIS and it's service pack are you on? I would suggest you contact Support Services to find out what is really happening.
Here is a blog that discusses how to adjust the background processing. Can you provide any other information about the rasters you are trying to add? Location ? Network or Local? Bit Depth? Number of bands? File Size? When was the geodatabase created or does it happen with a new one?