MySQL INSERT - When to Use HIGH_PRIORITY with Webpage

I've been having some problems inserting records into a mysql db -
through a php page.

According to php - the insert statement was correct, and everything was
working - ( mysql_query was returning true, and mysql_error() wasn't
returning any information). However, the new record was never posted
in the database -- and mysql_affected_rows() was returning that '0'
rows were affected.

Changing the INSERT statement to HIGH_PRIORITY seemed to fix this - in
that my record was finally added to the DB -- but, reading the mysql
documentation -- it doesn't seem like I should be using high_priority.

Basically, the documentation states that using HIGH_PRIORITY " also
causes concurrent inserts not to be used." .. isn't this kinda bad for
a website? I mean, feasibly I could have several people all hitting it
at the same time .. I can't have them ignored.

What's the proper mechanism I should be using? Should I be Locking /
Unlocking the table between inserts? Couldn't that also adversly
affect my users?