Errors are coming from http://localhost/teacherlogicxe/installchecker.asp or http://localhost/homelogic/installchecker.asp or a similar address. The install checkers will sometimes list all records from SLCommon.
The most-likely cause is you have a blank record in the SLSchoolSettings table. You should log into SLCommon. Click Inquiry. Click Manage Logic Connections. The form will almost certainly have two records: One for your valid data and the other will display Unknown... Select the Unknown record and delete it.