I’m guessing its your file? If it’s someone else’s file, they saved, but didn’t include the font files – have the client resave and send from illustrator with font files included OR convert to outlines and then resend. If it’s yours, either you forgot to save with fonts included or the font file was bad and couldn’t get imported (that happens with internet fonts). You may be able to get it all back if its giving you the option to locate the font file. Can also happen when you use a mac font on pc and vice versa. Also, if you imported the text, it may not read because it may have a link to the original text file which may not be available.
Fix (giant maybe?): try putting the AI, font, and/or text files all together in one folder (use copies not originals) and try again. If you have photoshop or other raster image files in there, try that. In the future, remember to check the font box and PDF boxes when saving as an illustrator file. I remember in the past, these could be unrecoverable, but sometimes the fix takes.
Save early. Save often.
Jonathan Ziegler
http://www.electrictiger.com
520-360-8293