Strange, I'd think the
.partxx.* part of a filename indicates RAR archives... Unless you obtained ace'd up rar files to distribute them over multiple briefcases, I think you should try to open 'em up with WinRAR.
Anyways, a *.c00 is a valid ace file, but only the second file in the total Ace archive: you're probably missing the first *.ace counterpart in this set, i.e. "C&C+renegade.part02
.ace".
Heh, disregard this post if you think it's weird, I'm betting someone who actually uploaded the game might have a better answer.