Looks like bracketology to me, Niraj. Without diving too deep into your code, it appears that you've nested some URLEncodes inside each other and they're not all closing where you probably want them to.
& "&rdr=" & URLEncode(URLRoot() & "db/xxxxx?a=API_EditRecord&apptoken=xxxxxxx&rid=" & URLEncode ([Related Store Item])
& "&_fid_14=" & URLEncode([# of Features Requested]));
& URLEncode("&rdr=" & URLEncode(URLRoot() & "db/xxxxx?a=dr&rid=" & ([Record ID#]));
The first URLEncode in that portion isn't closed until the end of the following line (could be intentional). The final line is short a close paren. You also have what looks like a stray ; at the line before the one you said is throwing the error.
