inserting multiple values in version 8.1.5

Hi
I am trying to insert multiple values into a table like this.
INSERT INTO tab_name (col1, col2) VALUES (val1, val2), (val3, val4)

This works in postgres version 8.2.1

My production server runs in 8.1.5. It gives me
ERROR:  syntax error at or near "," at character 35

What to do?
thanks