However if you enable all CLR exceptions to break into the debugger you will see an exception e.g. in this case "1,444.66 is not a valid value for Decimal". You can then get the call stack at this point and determine where the code is failing.
The data grid seems to handle quite a few exceptions silently which can cause confusion sometimes. If you are experiencing any odd behaviour with the Data Grid I strongly recommend you enable all exceptions to break into the debugger. To do this from Visual Studio .NET perform the following
- Select the Debug menu
- Select Exceptions
- Select Common Language Runtime Exception.
- Change "When the exception is thrown" to "Break into the debugger". This will apply the setting to all exception types unless you've overridden this.