message appears when trying to update or install programmes such as quick time or itunes message reads--installation package could not be opened,yerify the package exists & you can access it---using XP sp2 and IExplorer

Hi, You may try the suggestions given in the link given below and check if that helps to resolve the Windows Installer issue.How to resolve Common "Windows Installer" Problemshttp://support.microsoft.com/kb/555175 Hope this information is helpful.Amrita MMicrosoft Answers Support EngineerVisit our Microsoft Answers Feedback Forum and let us know what you think.