"Your client database could not be loaded or created. This is a serious error, reports will not work properly." is returned when logging into SMS setup utility.
User Permission Issue
This error message is generally related to the security permission of the ClientDB.mdb file in the \PowerLogic\SMS\ directory. If the logged in Window's user does not have permission to Read & Execute, Read, and Write this error will be displayed. The most common scenario is a user logged in as a Power User and the Power User group does not have these permission on the file. To correct this, right-click on the ClientDB.mdb file, select Properties, click on the Security tab, and click Add. Add the Power Users group and allow Read & Execute, Read, and Write permission. Depending on the logged in user, a different group may need to be added.
Full Hard Drive Issue
A possibility is the hard drive that the database is installed on is full.
A less likely scenario, is a corrupt installation of Microsoft Distributed Access Controller (MDAC). Please see the following Microsoft KB article for instructions on obtaining the latest Jet 4.0 SP install.