Problem with uploading custom logo?

Hi!

I am currently using Grid theme, one of the free themes on WordPress.

Today I tried to update a new custom logo to the theme by going into the “Grid Settings”, entering the new URL of my new logo. Once I save the weird thing happens.. the site refreshes and says “Grid theme updated” and all text-boxes are reseted.

What’s going on? I am semi-freaking out since my portfolio is live and soon to be shown to Architect firms…

my website: http://xinga.li/

I have tried to:
– Delete my cache
– Resize the image to fit the exact px
– Tried both .png and .jpeg
– Tried on two computers
– Tried in Safari, Chrome, Firefox and Explorer