Why can't I download apps on my android phone?

When I tried to open apps (the ones from the android market that i downloaded) and it said something like it cant open it. Then I deleted all my apps and see if I could put them back on. When I tried to download one it says "Application cannot be...

I just bogut a lg gt540 optimus phone but i dont know how to download apps on some andriod phones there is an android market but i cant find it on my phone. So is there something wrong with my phone or is there another way to download and if there is...

i mean whats the point of having an android if you cant download any apps also he thinks a phone is ment to call people and maybe take pictures that's it. I've tried to reason with him saying how this is the future. And everything I mean whats the point...

Hi I'm just asking how I can download or use apps that are not from the android market on my xperia x10 for example I'm trying to root my android because I have the 1.6 android software and I found online That I can root my phone using the app called...

there is no "market" instead it "storeffront"....wtf is that??? all u can get off that is wallpappers and games...i need GPS and i dont even kno how to get it....or if i even can for that matter. when i bought the phone i was informed...

I can access apps already on my phone but I can't download anymore. I have wifi. My sister got a new phone and we have the same old phone but she can download apps. Its the Samsung Galaxy S. And when I try to download an app when it stops it says package...

My polaroid internet tablet says that i cant download apps from android marketplace because there are no Android phones assciated with this account but i have a tablet so how do i get apps

I can access apps already on my phone but I can't download anymore. I have wifi. My sister got a new phone and we have the same old phone but she can download apps. Its the Samsung Galaxy S.