Thanks. Yes, it gives the following error: The backup disk image "/Volumes/backups-1/computername.local_macadress.sparsebundle" could not be accessed (error -1). Keeping in mind that "computername" and "mac address" show the actuals.
That's odd. Time Machine uses that name format on Leopard, not Snow Leopard, although it will recognize one it made under Leopard after upgrading to Snow Leopard. (On Snow Leopard, the MAC address is in a file in the sparse bundle, not part of the sparse bundle's name.)
Worse, in Iomega's setup instructions is this:
*2. Type +defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1+ to enable Unsupported Network Volumes for Time Machine.*
That means it is not an Apple-supported destination for Time Machine backups. It also means you probably won't be able to do a full system restore, either. See the pink box in #2 of [Time Machine - Frequently Asked Questions|http://web.me.com/pondini/Time_Machine/FAQ.html] (or use the link in *User Tips* at the top of this forum).
You may be able to get this to work, to a degree, but you'll have to use Iomega's instructions, and get any help from them.
There are some alternative ways to back up with Time Machine; see the rest of #2 in the FAQ.