Getting an "System.Exception" error when trying to change the data type of a column from date to (4335661)

Getting an System.Exception error when trying to change the data type of a column from date to datetime with the alter table option.
See complete error message below:

System.Exception
Error on extended region.
Message : Ungültiger Objektname sysproperties.
Stack Trace:
bei Quest.Compare.Schema.MSSQL.DBModel.Loader.CNSSysDatabase.FillDataSet()
bei Quest.Compare.Schema.MSSQL.DBModel.Loader.CNSSysDatabase.FillDataBase()
bei Quest.Compare.Schema.MSSQL.DBModel.WrapServer.CreateDB(ICNSServer iServer)
bei Quest.Compare.Schema.MSSQL.Scripter.CNSMSScripter.FillRootNode(Int32 index1)
bei Quest.Toad.SqlServer.Doe.CNSScripting.CNSScripter.LoadObjects()
bei Quest.Toad.SqlServer.Doe.Tables.TableProperties.get_Scripter()
bei Quest.Toad.SqlServer.Doe.Tables.TableProperties.getAlterSQL(Nullable`1 useExAlter)
bei Quest.Toad.SqlServer.Doe.Tables.TableProperties.GetScript(Nullable`1 useExAlter)

Using SQL Server 2008.

Steps to reproduce the problem:

1] Go to Object Explorer
2] Select a table
3] r-click and select Alter table
4] Select a date column and change the data type to datetime