If the error message you were getting while trying to edit your posts was something like the following, then it was due to the spam filter. The forum software's spam filter won't allow editing of posts if they contain links or if you're about to add one. This includes images hosted on external sites. This is quite annoying, yes, but it is there to prevent spam. If there's an emergency or an important change to be made, either contact a moderator to edit the post for you (if it's
very important, that is) or create a new post (not a topic) for sharing the link (which would be an acceptable exception to the bumping rules).
Your content can not be submitted. This is likely because your content is spam-like or contains inappropriate elements. Please change your content or try again later. If you still have problems, please contact an administrator.
As for creating new posts, there should be nothing preventing you from doing that. Posts will be put under moderator preview if they contain links and you have less than 5 posts, but they are usually approved within an hour or so.
However, both these restrictions should have now been lifted as you have at least 5 posts now.