The URL might have been correct, but it was posted incorrectly, i.e., you used the entire, huge, URL as the description which made your post extremely wide, which causes people to have to scroll left and right to see every post in the thread. You had also forgotton the closing {/URL}, so people could not just click on the link. Please repost your message.
Here's my standard message when this happens
MikePA: Cleaned up long URL. Please review your message before posting it. It's simple not to do this. Just insert a descriptive word or two between the {url=http://whatever}<font color="red">Enter words here</font>{/url} instead of the entire URL. Replace parentheses with brackets in previous example.