RegEx error | function template

With the same old webhosters as the previous issue, I get:
Parse error: syntax error, unexpected '^', expecting ']' in ......tinyfilemanager.php on line 3137

After checking the culprit is in re=/<%([^%>]+)?%>/g. the % sign is trouble!
I changed it to re=/<\%([^\%>]+)?\%>/g and it "seems" to be working... An old javascript trick?

I'm not an regexp expert so not exactly sure about the test(s) I should do to confirm.