Hello,
that is quite a really stupid error by me, and something too unfortunate to hold you back for.
Parse errors are a type of syntax errors. It told you that you have an unexpected '{'. This usually means that you didn't connect a string correctly ("Hello"."World"), or that you didn't close parenthasis correctly.
I made an "if" condition opening one clause ("(") and then a function, mysql_query, resulting in opening another clause ("("). Tha thing is, I only closed one (")") so that the curly brace ("{") was unexpected, instead of another closing parenthasis (")").

So, the correction is to be:
if(@mysql_query("UPDATE test_table SET ".$temp[1]."='".$temp[0]."';")) {

Good night!
Shaffer.