Using Delphi and FastReport I get this error message while debugging inside Delphi immediately after this line:

```
<FastReport_Component>.ShowReport(true);

```

Then this error appear:

> 
> Project myapp.exe raised exception class EVariantTypeCastError with message 'Could not convert variant of type
>  (String) into type (Double)'.
> 
> 
> 

It appears twice before displaying the report. but if I run myapp without debugging no error message appear.

How I can find which memo cause this error ? the report has so many memos. some has also expressions inside using `IIF` and the error message does not display any more info.