I don't understand your question. Do you mean the inventory extension? Like this Magento Inventory: https://www.magestore.com/magento-erp-extension

If you have any trouble with Magento extensions, you should contact the provider as soon as possible.

Updating the inventory in OpenERP based on stock from magento is not a good idea as OpenERP should take care of inventory management and this inventory should be exported to magento.

Openlabs has developed a new connector between openerp and magento which takes care of this. This has been written from scratch with a new design which is clean and simple. The module is also documented to explain the installation processes and the working of module.

The code is available at github.com/openlabs/magento_integration