Hi rvsr,

Can you explain your current situation in more detail? Are you saying that you cannot log into the DE org, so you can't complete the portal to community migration? Or that you are able to convert the portal users?

Some Salesforce info:

You don’t need to convert your portal licenses into community licenses, but you can swap some licenses for Communities licenses by either editing the user record or by disabling and re-enabling the external user. Note: If you decide to convert your portal licenses into Communities licenses, make sure
that the new profiles related to the Communities licenses have exactly the same permissions and object access as the portal licenses.

To disable a contact as a customer user so that you can assign them a Partner Community license:
1. From the contact’s detail page, click Manage External User, then select Disable Customer User. This disassociates the contact from and deactivates the user record.
2. Go to the account for the contact, and ensure that it is enabled as a partner account. If it isn’t, click Manage External Users, then select Enable as Partner.
Note: If your organization has person accounts, they cannot be used as partner accounts. Only business accounts can be used as partner accounts.
3. Go back to the contact’s detail page, click Manage External User, then select Enable Partner User.
4. On the User detail page, select the Partner Community license and associated profile. Enter other user information and click Save.

Thanks,
Phil