Software update does not recognise that I require the 3.0.1 update so I download it via apple downloads, however when try to install the update the installer tells me that I don't have Aperture 3, which I do of course, I did not have this problem with the Digital Camera Raw 3.0.1 update that installed no problem
I seen a tread that said to delete the com.apple.AECT.plist file but it is not present in my libary.
Any help would be appreciated
UniBody MacBook Pro 2.4 Ghz, Mac OS X (10.6.2), iPhone 3GS 16GB Black
Is Aperture 3 in the Applications folder? Is it named Aperture? If the answer to either question is "no" that would explain your issue. Renaming or moving an application from where an update expects it typically causes the update to fail.
When you say the AECT file isn't present in your library, are you speaking of the library in your user account, or the system library on your computer. If it's on your computer, it'll be in the system library (the one that starts at Macintosh HD, rather than the one that starts in your account).