Stock settings aren't "sticking"

Trying to add a Sold Out icon to my sold out products. I make the change, click save, and the setting isn't "sticking".

Steps I took..

Go to Admin > Configuration > Stock.

Select “Show Sold Out Image in place of Add to Cart”, select “1”, and click on the “update” button.

So I ran a quick piece of SQl to force the change, and it works, but if I go back to Admin > Configuration > Stock, the setting is AGAIN wiped out..

Interestingly, this is a 1.5.4 upgrade that I just transferred from my server to the client's server, and on my server I am NOT having this issue.. Stumped.. Anyone run into something similar?? Is there something else I can check???

I just transferred from my server to the client's server, and on my server I am NOT having this issue
What php version on the clients server?? Your server??

Thanks for checking in.. Gonna ask the admins to close this one.. after having some food and more caffeine, I took a look at the issue and realized this is a symptom of how the POSM module (commercial attributes manager like SBA,but IMHO better) appears to be overriding some of the default ZC stock settings..

Back in Stock Notifications is not playing nicely with the POSM.. The Back in Stock Notifications buttons were not showing when/where they were supposed to because of some code conflicts, and the ability to show the out of stock buttons using the default defines and functions is overridden by some of POSM's features.. I had to change the way BISN was implemented to make the two play nice together.. Doing this also fixed some of the things BISN was doing which blocked some of the POSM displays... the changes were all minor, and anyone using any other stock management module will likely need to make similar changes if they are using BISN.. so I am going to share my findings and solutions with the forum eventually..