Hi markossiotis,
Welcome to the Sony Community!
I suggest running the PlayMemories Home Settings Initialization tool to help resolve the issue. The program will be restored to its default settings. Once you finish adding the folders you want PMH to manage for you, the next page would ask if you'd want to use PlayMemories Online. You can skip the setup or log in to your existing account through this page. After the initial setup is finished, the PlayMemories Online tab will show up on the Tool bar.
NOTE: PlayMemories Online is not supported in some regions.
For further assistance with your concern, we recommend visiting our Sony Global Web site, http://www.sony.net/SonyInfo/Support/, for information on contacting the Sony Support Center in your region.
If my post answers your question, please mark it as "Accept as Solution". Thanks_Mitch