Assuming you've installed a nightly build of v7, and assuming that the module update mechanism within OpenERP isn't solving your problem, then switching to a newer nightly build could be the only way out.
Do not uninstall. We will overwrite the old with the new.
Download the newer nightly build installer. Stop the OpenERP service. Start the installer. When it comes time to select the folder where to install, select the same folder as your existing installation. Be careful, the installer is configured to append a new folder name to the folder you select. You must make sure that only the name of the existing installation folder is written out, no more, no less.
Do not uninstall the old and then install the new. This will break your environment and be almost impossible to recover from.