Sounds like Oracle's infamous issue with LOB segments.
What you are doing (moving data from one tablespace to another via exp/imp) will work fine for everything but LOB data. For unknown reasons, Oracle insists on restoring LOBs to the same tablespace (by name) that they came from.
There are a few ways to deal with this:
- Move the LOBs to the destination tablespace before doing the export (or one of the same name, if these are being done on different systems)
- Recreate the Arsdigita tablespace, do the import, and then move the LOBs to the tablespace you want them to be on
- Use Perl to change the name of the LOB segment tablespace in your dump. This has always worked for me, but is highly unrecommended by Oracle. They worry about binary data in the dump being corrupted by doing this
*I* would consider this behavior to be a bug, but Oracle does not.