Umm no. @M.J KING
It has nothing to do with the echo() function, or at least it shouldn't.
SBP, you are inserting data into a MySQL tabe through the mysql_query() function, no?
Example:
mysql_query("INSERT INTO users (username, password) VALUES ('$_POST[username]','$_POST[password]')");
Try putting ") before the ; on line 4, because you seem to be missing the fact that the SQL query is actually unclosed.
An argument does not matter. The query just needs ") at the end of it.
See how it starts with ("? Well, there's no ") to close the function.
And if this insertion is within an argument, make sure you have the right number of curly braces ({ and }).