Unable to use apps that access the Internet on wifi I have recently had a pretty weird problem with my new LG Shine Plus which I hope you guys could help, here is what I did:

When I first sign up for the phone, I purchased a one month data plan just to try things out, everything was great and I was able to use the data plan and wifi when I am at home and downloaded quite a few applications and they all worked perfectly.

I cancelled a data plan since it cost quite a bit, however I am a student and there are both wireless networks on campus and in my residence room. As a result, I have turned off the Mobile Data Networks. 

After that, all the applications, for some reason, stopped working. When I opened up the Advanced Task Killer Free, for example, it will show You must have INTERNET and ACCESS_NETWORK_STATE permissions in AndroidManifest.xml and when I tried to hit KILL selected apps, it will crash. On Bloomberg, it says android.Manifest.permissions.INTERNET permission not set in AndroidManifest.xml file before crashed, and on a whole bunch of other apps, they just crash as soon as I open it up. 

However, the most interesting bit is, I was still able to access the Internet on my mobile browser (tried several website that I know I did not go before just to make sure those are not cached pages) on wifi and I can access Android market on wifi as well.

So I turned Mobile Data Networks back on in hope that would resolve the problem, but the same thing happened even with the Mobile Data Networks turned on and now I am unable to use any apps I installed  I have verified that I have the apn set up properly in there. 

By the way, I have link2sd installed, but it was installed while I was using the data plan, and it worked fine then, I have also had AdBlock installed, which I have already uninstalled it and even apps without any add (dropbox) is crashing at the moment as well.
At this point, I would suggest doing a factory reset. Your problem would likely require more troubleshooting than it's worth to fix. Make a backup if possible. Google should remember the free apps you've downloaded and re-install them.