I don't know much about Roxio but generally if you are writing your own compilation, as you add tracks you want to copy they are placed into the cache folder on you hard drive. If the project is 74 minutes long, that equates to about 650-700MB in size, which is far greater than the 84MB left on your drive.
Do you have another drive on your computer that you can move the cache folder to? You can probably do this by going to the options or preferences in the program and telling it what folder you want it in. If you don't have another drive I'm afraid your are going to have to free up some more room on your hard drive somehow.