file-format cannot parse the file.

hi im trying to get som .png's to open in photoshop cs and it keeps giving me this error message.
"could not complete your request because the file-format cannot parse the file."
what does that mean?
thanks

Strange,

Basically what PS is saying is : I see that this is a png file but the data in the file tells me it isn't. Then Photoshop gets all mad and doesn't want to play with you anymore. :D

Were the png files emailed to you?
Sometimes image files sent email get manhandled by ISP's on their way across the net.

Is it just (1) png file or ANY png file?
You could have a bad file.

See if imageready will open it/them.

Most of the time I see this error it is coming from a digi camera, and more often than not its because of an unformatted memory card.

Well it a lot of png's that my friend bought online for scrapbooking. She wanted me to see if I could do something with them for her. I got them from her computer via a flash drive and she got them by download.
I opened them image ready and it told me the same thing but it did open them after the message.
I can save them from image ready as a .psd and work around it i guess.
But is there a better/easyer way (I have a bunch of them)?