Data Migration

I get the following error when I try to import/ export from Excel in AX 4.0

"Error executing code: SysDictTable object not initialized.

(C)\Classes\SysDictTable\fieldName2Id

(C)\Classes\SysDataExcelCOM\readColumnDefinition - line 43

(C)\Classes\SysDataExcelCOM\readDefinitionWorksheet - line 53

(C)\Classes\SysDataExcelCOM\buildDefFromFile - line 33

(C)\Classes\SysDataImportExcel\importTable - line 4

(C)\Classes\SysDataImportDefBase\import - line 36

(C)\Classes\SysDataImportExcel\import - line 10

(C)\Classes\SysDataImportDefBase\run - line 5

(S)\Classes\SysDataImport\main - line 10

(S)\Classes\MenuFunction\runServer

(C)\Classes\FormFunctionButtonControl\Clicked"

Any help in resolving this is greatly appreciated.

Thanks