When connecting a new version of Projectwise Administrator to an older version of the Projectwise integration server datasource, the user is prompted to create tables.
Create Custom Database Tables: Do you want to Projectwise to create tables in the database? To create tables, you must be logged in as a database administrator. Make sure you log in defaults to the correct database tablespace.
Click cancel to the dialog to create tables and the user gets this error message.
Last Error 
Cannot login to the datasource
Database tables verification failed. One or more custom tables are missing.
The 'create custom tables' and the 58198 error messages are a result of connecting a newer version of the Projectwise Administrator to an older version of a Projectwise Integration servers datasource. The newer version of ProjectWise administrator checks and validates the tables it needs to function. If the tables are not found it prompts you to create them. If you have not upgrade your datasource to the same version of ProjectWise Administrator you are using, then click cancel.
In order to fix the problem you will need to clean up your ProjectWise install.
Did you upgrade to the newest PW Admin on your machine to match your PW Explorer client?