iPhone 3GS Application Install Failures

Hey, im running firmware 3.1.2 on my iPhone 3GS. It has been unlocked with blackra1n. Now I’ve downloaded some applications to install on the phone, but everytime I try to sync it sayd “installation of application failed” -> this with every application i tried.
Anyone know a solution? I also cannot connect to wifi.
Answer #1
Oh, Have you installed Cydia?
Step 1 – Start �Cydia� on your iPhone springboard.
Step 2 – Select �Manage� tab at the bottom of your iPhone screen and then select �Sources�.
Step 3 – Select �Edit� and then select �Add�. Now enter a url source. Type �http://apt.macosmovil.com� and select on �Add Source�. Once Cydia has added the source click on �Return to Cydia� button.
Step 4 � Once the installation is completed. Search for �AppSync para OS 3.1(3.1.2)� in Cydia and install it.
Step 5 � This app will automatically patch MobileInstallation file on your iPhone OS 3.1.2.
After this, connect your iphone to your pc and sync it with Itunes, then try to sync those apps, there should be no problems.
Enjoy. and about the WIFI, not very sure.., maybe you are trying to connect to a Password Encrypted network and you forgot to enter the pw? Sorry.
Answer #2
For the wifi try resetting network settings settings
general
scroll down to reset
reset network settings
Answer #3
Thanks for the info: @: I type the correct password, tried for 20 times no success.. Don’t know if i did anything wrong, i ran blackra1n and everything is ok, just can’t connect to a network with wifi.
@jeff: i tried this and then i had to run blackra1n again, i tried connecting after but still no success..
Answer #4
thx had same problem and it works now thx