If you are getting the message like “SAP object XXX cannot be assigned to package XXX” then it can be a good reason to check this post , i hope it helps you to eliminate the situation..

I would like to share an example with you..

Configuring SMW0 for this example ;

Creating object with object name “COMPANY.GIF”

Import the object and try to SAVE

After this , you should get the following message

Click the help button to see details

Go back and now try with creating the object with object name ZXXX

Import the related file again

Click the SAVE button

Now it should work ,you can import the object starting with “Z” to package started with “Z”