Help Opening EPS file in Photoshop 5 please

Hi
I have just found this forum, I hope it will prove an invaluable resource!
I run my own small business designing and printing 'DrumSkins' for bands,
my site is www.rockstarskins.com I use Photoshop 6 mainly, but in no way have I had any training in using it, so I get by with just doing what I can on it.
The reason I am posting is I have been sent a couple of EPS files and everytime I try and open them it say's
'Could not open (................) because the parser module cannot parse the file'
Now I always save the files I work on as EPS when I email them to my printer but I can not open EPS files people email me!
Any help would be great.I can provide dicounts on drumskins to you!!
Thanks
Scott

Ok, before I go blurting out what I think are the answers... I have a couple questions.

Is it just eps files from one certain client... or any eps file sent to you that you can't open?

A parser error usually suggest 1 of 2 things

1) Photoshop is confused by the header data in the file... ie.. it sees that its an eps file but in the header it finds something that suggests it isn't an eps file.

2) Its an eps files created by a later version then PS 5/6 will open.
ie... Illustrator/Photoshop CS

Are the clients archiving the files prior to emailing them to you or are they just shooting you the eps files unprotected?

Isp's can really manhandle your files while traveling across the internet, an unarchived file can result in a corrupt file.

I've seen this question many times...but I can't remember the answer.
Do a Google and Adobe search, I'm sure the answer it is there somewhere.

Good luck