Can't import .png's into Photoshop Cs3 Extended

[AaronAMV]

It keeps giving me this error:
Could not complete your request because the file-format module cannot parse the file

I've read this, but it's not helping me. I've tried importing it into paint and exporting it back as a .png into Photoshop, but it's still giving me a problem. I can't do print screen because that defeats the whole purpose of the .png.

I'm trying to create my first serious sig, so help would be appreciated. If worse comes to worse then I'll just mask out what I want, and drag it like that, but if I don't have to, I'd rather not.

Thanks in advance.

[mirkosp]

Try tiff or tga instead. BMP if you have to.

[AaronAMV]

Okay, I restarted it, and it worked... This can be closed.

PS. Even though I got it already, thanks for the tip mirk.