Mysql / 4.x to 5.x user with Rt3

i know this is not a mysql maillist but i think it has to do with rt3.
Should i do something else when i use mysql 5 instead of 4 (i used before)
Cause i cant dump now rt3 for backup cause of a failure on Attachments
The other tables are “repaird/upgrade” successfull

when i make check tables attachments, i get the information
rt3.Attachments | check | error | Table upgrade required. Please do
"REPAIR TABLE Attachments" to fix it! |

when i do this, or mysqlcheck --check-upgrade --all-databases --auto-repair
all is fine, he says tables repair but the table is still (after a new
check) not “Upgrade” all other tables are.

Cause of this , i cant dump the database, (he crash, with this failure)
any ideas (?) it is a InnoDB Format.

i forgot to wrote what happens after repair
mysql> REPAIR TABLE Attachments;
| Table | Op | Msg_type | Msg_text |
| rt3.Attachments | repair | status | Table is already up to date |
1 row in set, 1 warning (6 min 30.36 sec)

friendly regards