cant open any apps on my ipad I got a iPad (1) and no mbp or windows for itunes so I hooked it up to another persons mac to get the latest updates for it.

It was all good for a while till the battery died the other day. After I charged it I was not able to open any apps except the ones that came pre installed.

not being able to play plants vs zombies any more makes me :( 

how to fix please
There seems to be an issue with the permissions for your ipad and the installed apps.  

Not sure if you've tried this.  But try installing any free application, the ipad will ask for your iTunes store password.  Once it has finished downloading, try and start another app.