I added the code tags for you. I meant to "Modify" your original post. Anyway ...
if ((musicValue) == 0);
{tone(294)};
This is wrong because the first semicolon terminates the "if". Two valid ways of writing it would be:
if (musicValue == 0)
{
tone(294);
}
or:
if (musicValue == 0)
tone(294);
They are both quite different to what you had. A semicolon terminates a statement. However since an "if" statement is recursively defined like this:
if (condition) statement
The entire thing is one statement (an "if" statement) and thus there is one semicolon at the end (but not after the round brackets).
The braces ( "{" and "}" ) form a compound statement, and in this case you don't use a semicolon (the "}" is sufficient to terminate it).
You could use "else" in your case because musicValue is hardly going be both 1 and 2, eg.
if (musicValue == 1)
tone(330);
else if (musicValue == 2)
tone(349);
else if (musicValue == 3)
tone(392);
... and so on ...
In this sort of situation a "switch" statement would be easier to read, eg.
switch (musicValue)
{
case 1 : tone(330); break;
case 2 : tone(349); break;
case 3 : tone(392); break;
... and so on ...
} // end of switch