My iphone 4 won't let me download app

I had instagram before, and I accidentally deleted it the other day, now i'm trying to redownload & it won't let me. It says open next to the app, and even when I try to open it, it won't. I've restarted my phone, I've connected it to my computer and everything. What else is there to do?

How to create an iphone app on a windows computer?

I really want to create an iphone app, but I can't seem to find a free way to create it on windows. I heard that you needed a mac to get the proper software for ios application development. But I was just wondering if there was a free way to do it on Windows? I just want to be able to create the app and test it out on my Iphone. If it's good I'm willing to spend some money to get it into the app store. Any advice is appreciated, thanks.

How to get chocolate out my iphone 5?

Okay well this idiot decided it would be funny to throw a chocolate button at me, it fell into my top pocket where my phone was but i never noticed, it then melted and it has went into the charger point, speakers and earphone slot, i managed to get the chocolate out the earphone hole but the speakers are still covered and so is the charger, my friends suggested using a tooth pick but i can't because that will just lodge the chocolate deeper into the speakers and the charger hole. They also suggested i used a hair dryer to melt it out but i'm not sure if that will work or break the phone by over heating it? Could someone please help me with a suggestion of how to get the chocolate out?

What does jail-breaking mean?

Every now an then I hear people jailbreaking their iPhones and android devices, etc
What is it? Is it good or bad? If it's bad, then why isn't it banned?