iPhone build error | Codesign failed with exit code 1| object file format invalid or unsuitable

Recently, I have installed Xcode 4.x, this have shown weird errors with existing app , and asked for a lot of change to make it compatible with new complier.
Project timelines are always important, So I reverted back to Xcode 3.2.6

Everything went Okay. But when I tried to apply ( code signing) provisioning certificates to install application into iPhone, Build Failed with error;
Command /usr/bin/codesign failed with exit code 1
with description-
{*}.app object file format invalid or unsuitable


Then I moved to the solution library of developers (stack overflow), As most of the the developers do :)
After spending lot of hours, Saw this answer by emcmanus.

sudo mv /usr/bin/codesign_allocate /usr/bin/codesign_allocate_old
sudo ln -s /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/codesign_allocate /usr/bin


Tried first command, Blindly..
My terminal CLI answered : No such file or directory!

Then, I Explored /usr/bin folder, and observed yes! It was not there. (there is nothing to keep as back up , after renaming it. Symlinking is the ultimate goal )
I run "sudo ln -s /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/codesign_allocate /usr/bin"
to create symlink.
and YES! symlink did the trick...


Excellent... Hope this will do the trick for, who is in this trap :)