Import involves creation of new tables in the database, which is not permitted in single user mode.
The reason for this is to prevent multiple people trying to change things at the same time, or other such actions that would lead to bad things happening. For instance, consider what would happen if a table that was in use by other people was deleted.
For this reason things that modify the database structure, such as file import, must be done in single user mode.
Are you refering to the oracle priviledges?
If so then the oracle privileges needed are described here:
(actually these are more than you actually need for oracle, but they will work).
When you first connect to the database from IJC you need to follow these instructions.
Once set up you connect to the IJC database as described here:
If you need to have a multi-user system (e.g. add multiple users each with their own IJC username and password) then you must set up security in IJC and specify permissions. Look here for details (and the links at the bottom of the page):
Logging in to the database once the connection information is defined is described here:
I hope this helps.
The link is corrected.