installation manger not being recognized

When I click on Control Panel/ Add and remove program /Solidworks 2008 SP4.0 Installation Manager / change , I get amessage "Solidworks 2008 SP4.0 Installation Manager is notrecognized by the operating system as being installed, re installit from the source disk" . the problem my source disk is SP3.1.What should I do?

Not that installation manger is completely functional.


i a appriciate any help

SolidworksAdministration