Error: "Object [MySQL EC2 Schema] already exists "

Hi all,
since I installed PDI 4.2.0, I face an annpying problem:
importing a transformation from XML file, when I save it to the MySQL repository PDI gives this error message:

Object [MySQL EC2 Schema] already exists.

Even with this message, the transformation is saved correctly in the reporitory
This doesn't happen with jobs, but only with transformations.
I didn't find any EC2 Database in my MySQL DBMS...

I upgraded to PDI 4.4.0 and the problem persists.
I'm sure this is due to my data in the repository, but I cannot understand which data.

Can anybody help me?
Any idea will be appreciated.

Thanks a lot

Andrea