NullReferenceException after catching “A generic error occurred in GDI+.” error for excel file

Hi
I have a strange error after catch the error "A generic error occurred in GDI+."

when i try to open an excel file trought the instruction :

Workbook workbook = new Workbook();
workbook.LoadFromFile(FileName);               

but few minute after catching this exception my application craches (NullReferenceException )without specifying the location of the error !!

knowing that it happens when i try to scan an excel file, but it work for others excel files !!!

Could someone help me in this topic ?

Tags: C#, GDI+, Microsoft Excel