Aditi, I noticed you haven't seemed to get any responses. I can tell you at least that this is not a bug with Protege 5.5, most of us have been using it for months and it works just fine. So it has something to do with your installation. It's hard to give more feedback based on what you said.
For starters what platform (OS and version) are you running on? If you are running on the latest Mac OS (Catalina) that may have something to do with it. I don't think anyone on that platform has experienced that particular problem however there has been at least one issue with it where Protege 5.5 hangs when trying to open ontologies. How much RAM do you have? What version of Java is installed on your machine?
Also, when you say you are unable to see forms can you be more specific? The Protege UI is defined by tabs and views. The tabs run across the top and give specific configurations such as Entities, Classes, Individuals by class, SWRL tab, etc. Then each tab consists of several panes called views, e.g., the Individuals by class tab has views such as Class hierarchy, Direct Instances, etc. So when you say you can't see forms do you mean that some of the panes in a tab don't show up or that some tabs don't show up or that none of the tabs show up? Can you include some screen shots in a message?
If you give us more info then we might be able to help you figure out the problem.