I followed the link and end up on the problem with mysql 3.23 not supporting multitable delete statements.
Workaround for subselect in delete query
The multitable delete you have there should work totally fine in MySQL 4.0, however 3.23 doesn't have multitable delete statements.
In 4.1 you could either use subselects or the left join (the left join being more efficient most likely). In 3.23, which I assume you are using since you got
a syntax error, you will have to do it client side. You could easily make MySQL return the actual select statements you need to run and just pipe them back to MySQL or something similar.