This will be impossible to help with, since there is really not enough information.
You say it is a simple product, but from the error you can clearly see that something is trying to use configurable product type functionality. This is most likely caused by some 3rdparty code/custom code that is not correctly determining the product type, and then trying to load configurable product child products.
You need to find that code.
Your best way forward is to use a debugger.
Since you know where the failure is happening:
home/ottocap/public_html/app/code/core/Mage/Catalog/Model/Resource/Product/Type/Configurable/Attribute/Collection.php on line 160 you can simply place a breakpoint on that line, wait for it to break, and then step backwards via the call-stack. You will literally get the calling code in a matter of seconds, and from that determine what is up.