update_post_meta Function Not Working 100%

This is on WP 2.7.1

I was having issues where post meta data ws not updating and I finally narrowed it down to this simple test:

update_post_meta(91, "mytest", $mytest);

The $mytest variable = 1 (local variable)

mytest key exists for post 91 and is currently set to zero (0)

update_post_meta() is not doing the update with the local variable, however, if I change it to this:

update_post_meta(91, "mytest", 1);

…it works.

I know $mytest = 1 because I put this line right below it:

add_post_meta(91, "mytest2", $mytest, true);

(mytest2 entry does not exist and is created by this line).

So it fails to set mytest to 1, but DOES add a new record for mytest2 that is set to 1.

Weird!

Been trying to code around this, but anytime I stick a variable in there, add_post_meta doesn’t do the update, but when it’s a hard-coded number (constant), it DOES do the update.

Anyone see this before or have any ideas?

Thanks!

John