File upload stopped by extension

[mirageaus]

Hi,

I'm trying to install the e-commerce software 'PrestaShop'. It was working perfectly until the very last step of installation, in which I have to upload a logo for the site. Unfortunately, every time I try to, I get the error "File upload stopped by extension." I can't bypass it in any way (I tried uploading my file in the same spot that the default logo is, but it still doesn't let me skip that step). Any ideas?

 

[bugfinder]

Whats the file extension?

 

[mirageaus]

I have no idea, thats all the info it gives me.
Edit:
I've put in a support ticket for it.