>I select records into a cursor (MyCursor2).
>Then I want to make this Cursor updatable, so I use this syntax:
>use dbf('MyCursor2') again alias MyAlias.
> It gives me an Error on this string, saying 'File ... not found'.
> I put suspend before this command and see, that this cursor is actually created.

What does DBF('MyCursor2') return?
Do you need a NOFILTER clause on your select? IOW, are you getting the table used again with a filter?