Drop user fails with ORA-01418

Hi everyone,

I'm pretty sure, many had run into this problem before and can provide some help.
When I try to drop one of my user, I get the following:

SQL> drop user theuser cascade;

ORA-00604: error occurred at recursive SQL level 1 ORA-01418: specified index does not exist

What index it's talking about, metalink says this is related to some data corruption in data dictionnary, but doesn't provide a solution.

We run Oracle Database 10g Release 10.1.0.3.0 on Linux.

Thank you.

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