.dmg files are for use with Mac OS X. Some have suggested ways around this incompatibility. See links.
Normally, printer driver files (printer extensions) reside in an Extensions Folder (in the System Folder). To make things easier, downloads may contain an installer.
Epson has a printer driver download that possibly could be useful in this case. It is in the form of a BinHex (.hqx) file. If downloaded via another computer, keep the .hqx file unaltered until on the Mac with the printer. Then use StuffIt Expander to decode the BinHex.
Some troubleshooting information for the Stylus Color 980 can be found in a Printer Basics document at Epson's support site.
Thanks all... but it wasn't that simple. (Nothing in the IT world ever is) We have a very specific use for the mac we use, and I failed to realize there was more to it than what I prepared for. We lost all the specfici settings for the printer, but the real problem was Stuffit Expander. The engine for the install of Stuffit on the replacement mac was damaged, so no files could be extracted. Every attempt I made to move .sea files over still left them corrupted ( I can only assume that is due to downloading them on a PC and writing them to a CD for a trip over).
Another problem, almost ALL of the archived downloads of Stuffit Expander I found, were, you guessed it, compressed into something that Stuffit couldn't extract. So after hours of searching the internet, I finally found an ancient version of stuffit that was in .sea format, found a way to hook the old ancient mac up our network by running Ethernet cord to it, downloaded the .sea Stuffit installer onto the Mac, ran it, and voilà. Printer was installed, and all that was left this morning was tweaking the margins and print size.
I am suddenly reminded of two things... I hate that my hands are tied as far as upgrading machines, and that I am so glad we only have one mac...
I use the Epson Stylus Color 740, 900, and 980 models with pre-OS X Macs. To avoid potential conflicts, you should disable the following Apple printing extensions when using an Epson printer: (1) Desktop Printer Spooler, (2) Desktop PrintMonitor, and (3) PrintMonitor. The Epson equivalents for them are part of the driver installation package. You can use the Extensions Manager Control Panel or manually drag them to the Extensions (Disabled) Folder and restart the computer.
Good to hear that you found a solution.
Just a couple of comments.
>I can only assume that is due to downloading them on a PC and writing them to a CD for a trip over
Yes, the resource fork of the Macintosh file had apparently been lost/damaged. A self-expanding archive (.sea) file would normally act as an application on the Mac. If something has happened to the resource fork, the self-expanding capability would have been lost. The data fork would still be there, though (and in case of a StuffIt format .sea, it can be opened/decompressed by a working StuffIt Expander).
In order to protect Macintosh application files on the Internet, a BinHex (.hqx) or a MacBinary (.bin) encoding is used. The encoding can be seen as a shell around a Mac file. StuffIt Expander can be used for the decoding on a Macintosh computer.
A plain StuffIt compression (.sit) may work well for protection as well.
If an encoded file has been on a PC, one should not expect it to automatically open StuffIt Expander once on the Mac just by double-clicking. Instead, drag the encoded file onto the StuffIt Expander icon, or open it from within the utility.