OK, we have a solution!
Make sure you understand what caused this problem:
iTunes 7.4.2 updates the mobiledevices.dll that Jailbreak uses, this causes private functions to misplaced. So if you want to jailbreak using iTunes 7.4.2 you *MUST* use an UPDATED version of INdependance 1.1.1 or AppTapp 3.0. Otherwise, your phone will go into an endless reboot loop.
Beside from that, there is no danger in using iTunes 7.4.2 none what so ever.
If you were unlucky enough to try old jailbreak with new iTunes 7.4.2, and got endless reboot loop here is what you to do solve it:
1.) Make sure you have iTunes 7.4.2 intalled
2.) Make sure you have AppTapp 3.0 installed
3.) Make sure you kill iTunes and iTuneshelper using acitivity monitor
4.) Put your iPhone into recovery restore mode (yellow triangel) by holdning down sleep and home button together for about 25 seconds.
5.) Now start AppTapp, but do not click anything
6.) Open Terminal, cd to the AppTapp application, into Contents/Resources/
7.) now type ./iphonecomm -s 4
That’s it, you should be out of reboot loop, and you will be able to activate/jailbreaking using the AppTapp 3.0 application.
A big big THANKYOU to ender-iii from apptapp!! They have posted futher instructions at http://iphone.nullriver.com:16080/beta/
link al foro.