Your regex is matching the entire tag, including everything between the "<" and ">", and replacing that with an empty String. But it sounds like you want to match "<" or "</" or ">" or "/>", and replace only these with empty Strings.
Does that make sense?
"We're kind of on the level of crossword puzzle writers... And no one ever goes to them and gives them an award." ~Joe Strummer sscce.org