i have a problem that when i login this appear to me This package can’t be installed.
There are problems that prevent this package from being installed.
Sorry you're stuck but there's almost always a pretty easy fix! Do NOT try to start all over again, eg. uninstall Max's Pitch Package, etc. That can make things worse.
Before you post make sure you check the Help FAQ for an instant solution first. Then, if you can't find it there, you can post your problem here and we'll get to it ASAP (within 24 hours), but be sure you:
post in the right category
INCLUDE AT LEAST ONE SCREENCAP IN YOUR POST TO SHOW THE PROBLEM!!!!!!!!
explain the problem clearly
Always best if you add a screencap to show what you're seeing as mentioned in the instructions above.
But from what you are saying, it sounds like you might have gotten the wrong type of account - the 30 day free trail account by going straight to the Salesforce website rather than following the link that Max gives in the instructions to get a Developer Edition account. The 30-day type will definitely NOT work for these exercises. I can't tell for sure without seeing your screencap but if that's what you got, you need to abandon that and get a new account by following Max's instructions.
Let me know, ok?