Some days before I have upgraded operating system in my MAC PC from Mac OS X Snow Leopard to MAC OS X lion. After updating operating system in my computer it has started giving me problem. Now whenever I try to update application at that time I get permission error. I have tried to find out solution internet regarding this problem and I come to know that I have to delete old application from my system and download new version of it and install it but it is not good idea to remove each application and download new one again. Please let me know what should I do to update application in my system. Thank you in advance.