HELP!!: Memo too large / Field is not a BLOB error

Hi,
In a Paradox table I have a string field size 100 , I edit this using a
common DBEdit field and everything works fine.

Then I decide that I need a field of type Memo to store this information.
I change the field type from string to memo in the actual table with
Database Desktop / Restructure, the size of the memo is 100 as the string
type was.

I erase the former string type field in Field Editor and adds the new Memo
type field, so the field type change shall be recognized by the system.
Finally I change the DBEdit field type to DBMemo type and run the
application.

When I now enter Edit mode the new Memo field content is "(Memo too
large)", and I can't edit or erase it.  When I try to save the record with
this Memo field the error message "Field is not a BLOB" is displayed.

Why does this happen?  I thought it should be simple to alter a database
field field type from string to memo...??  

Any answer is HIGHLY appreciated....

Please copy any answers to bush...@sn.no.

Regards from Tor