A quick offering to the great Google god, in case you are running into the same issue:

• “NullReferenceException” in the “ExtractValuesFromCell” method – this is caused by the “pseudo” cell added by the SlxGridView. To work around, turn off the “ExpandableRows” flag.
• Blank page with a NullReferenceException in the LookupControl ClientConfiguration.From method: check the provider listed in connection.config. It needs to be spelled “SLXOLEDB”. If it is spelled out “SalesLogix OLEDB Connection Provider”, it will fail (not sure why but on 7.5.2 sometimes the connection is output in that format – I think, because I created the connection in AA, instead of logging into the Admin first)
• Web client crashes when grid.Sort is called – do not call that method from the Sorting handler because it will cause infinite recursion (the Sorting handler can often be empty)
• AA gives ArgumentNullException when Update Properties is clicked: this is an installation problem. Run a repair. In fact, if you get random errors from AA, and they are not specific to one project, running a repair should probably be the first corrective action.