Can real media (RAM) files be brought into Vegas? I'm getting an error when I try. I searched this forum and didn't find anything on it, which surprised me because so many things get discussed.
No, they can't be. The licensing from RealNetworks forbids it.
If you look at the file types that Vegas can work with in the specifications you'll see that both import and export are checked for everything except for Real and AC3, which show export only.
I think the perception at the time that Vegas 4+DVD was released may have been that the largest use for importing AC3 would have been illegal ripping of commercial DVDs. Any other use was probably considered inconsequential so there may not have been any strong drive to include the feature.