Problem with Software Update

Hi - apologies if the solution to this has already been posted. I have checked, but can't find my issue anywhere...

A number of apps on my iMac (including Airport and iWork) are telling me that there is new software to be downloaded when I open them. I follow the prompt to download the software through Software Update, but this says that my computer is up-to-date...?

Any ideas? I have deleted the cache, and this has not changed anything.

Any assistance, greatly appreciated.

Dave

 

Does anyone have any ideas?