The Acer disk probably requires the HDD recovery partition to work.
Just download a legit full Windows 7 trial install image from DIGITAL RIVER
and burn it to a DVD, install and then use your Acer key (off the sticker on your computer) to activate -- just make sure to get the same version, i.e. like Windows 7 Home Premium 32 bit, as what you had on the machine.
edit: also it is best to download the latest drivers from Acer for your model to use following the Windows install.