db2 has drop database to remove the database and all its catalog.
Check where are you creating a container and the database_path.
If another database is using that container , then db2 will not allow you to
create the database.
As a last resort use db2untag command, but I strongly recommend
consult IBM before doing anything like that.
Once you uncataloged the databases, Did you cleaned up or removed the catalog directories manually. Some time db2 does not clean up the catalog directories.
I haven't added any databases to uncatalog. I un-installed DB2 from my local machine, deleted the catalog directories (C:\DB2, C:\DB2CLTSV, C:\DB2LOG) and then reinstalled DB2. When I go to create a new database, that is when I get the container error.
You probably still have stuff under /sqllib that's left from your previous installation. Deinstall DB2, remove what you call "catalog directories", also find and remove a directory called "SQLLIB" (it's either in the root or under "Program Files"; use file search if you have difficulties locating it), then reinstall DB2.
Next time you do it don't forget to drop all databases before deinstalling DB2.