Check Technet, but that is the point of the files being encrypted; to not allow them to be viewable by any unauthorized persons.
 
Did he by chance have a backup of these files (using NTBackup or the like) that you could restore and try again with? Otherwise, it's over.

If, on the off chance, the computer belongs to a domain with an encryption recovery agent specified (i.e. the administrator account) you can use that account to recover the files.
 
If it's just a home computer with a local policy specified to allow the administrator account (if there is one!) to be the ERA, then you can use that login and may be able to recover the files.
 
Otherwise, it is as stated before... over.

so if files are encrypted and the computer crashes and you need to reinstall windows it is the same deal? That seems pretty fuked up to me

Not necessarily, as most people that use encrypted functionality would also be on a domain and retain their same account SID a (hopefully) remember their password. As shown below, backing up the key doesn't appear to be a big deal, and neither is assigning a recovery agent. It just so happens that the person that used encryption may not have actually read the documentation (or at the very least, didn't follow any of the recommended steps).
 
http://support.microsoft.com/default.aspx?scid=kb;en-us;Q308993

I read stories like this all the time and it really does sadden me that people do just rush into things without taking proper precautions.
No offence to anybody but it does always make me laugh when after something like this happens people just assume that encrypted files are really easy to get into and within minutes you'll have all your data back - kind of defeats the purpose of encryption don't you think?
 
I have a few encrypted folders on my home WinXP machine, I have certain files that I would prefer people not to be able to get to should my PC be stolen etc.
My keys are backed up onto floppy disk and this disk is locked in the safe at work.
Should the worst come to the worst I know that I can re-install the OS, bring my keys home and re-import them and all my data will be nice and intact.
128bit Encryption is not meant to be broken, when you encrypt files you need to make sure you don't lock yourself out and if this means hiding some keys somewhere really safe then you must do this.

Yeah, it's kind of funny when people want to feel secure about their files yet get mad when then there is no available (let alone easy) way to reclaim them when you have lost normal access. The whole point was to *secure* them afterall...

The double-edged sword of encryption strikes another blow...