app could not be installed in the itunes library because it is not a valid application

I made an adhoc build of my iphone and ipad app and sent to client.but the problem is that only ipad version he is able to drag into itunes.

the iphone version when he drags into itunes,it displays the error

"app could not be installed in the itunes library because it is not a valid application".

Both application works in my mac properly.what may be the problem the iphone app were made for 4.1 deployment target and ipad 3.2 is this any reason or is it that due to itunes version?

it seems really strange but the app could not be added to itunes and showed invalid app because the app name contained special characters!