Since Mup requires its input in a fairly strict format, when a song is put in, it may contain "typos." Generally, the error messages that Mup prints will give you an idea of what is wrong. However, sometimes Mup is not able to recognize that something is wrong until some distance beyond the actual error. If you can't find anything wrong with the line that Mup lists as being in error, try looking at the end of the previous line, or even earlier lines. Some of the most common problems are missing semicolons and missing quotes. Missing quote marks tend to be especially confusing to Mup, and may cause many error messages, even though there is only one problem. Another common problem that may cause a very large number of error messages is forgetting to state "music" to enter music context.