Where are you getting that URL from? Is it what you are seeing from the backend on the request, or is that what you must paste into your browser to view the page?
If the former case, then does your URL have special characters or white space within the name? If so, then those will be escaped out. I'm sure you may have seen %20 for example which is a space. The %28 is the "(" character and the %29 is the ")" character. So do you have a line that looks like
localhost.com/(S(iqlo5ypdbinj23wszegbmj0c))/Index.aspx
somewhere that is being sent to your host? Check your strings and make sure that you have opening and closing quotes on them all in the proper locations.