Logic not finding samples from third party software

Am running 10.6.5 on a 27" iMac i3. have the latest Logic update 9.1.3

I'd bought an instrument expansion pack made by AMG (Expansion Pack) a few months ago - installed it and it comes up in the Media library under "Shared Garageband Settings" - all the instruments play fine.

I've just bought another expansion pack made by AMG (Synthpack) - installed this and this too comes up in the Media Library under "Shared Garageband Settings", but when I click on any of these instruments I get the messages like "EX24 instrument "Wedge Bass.exs" - Audio File "0741 MiniMoog 48.wav" not found! and "EX24 instrument Juno Pad.exs" - Audio File "3031 Juno 108.wav" not found!

I've opened Garageband and can find and play all the instruments there - so I know they've all installed in Garageband o.k. But for some reason Logic can't pick up the samples in the shared Garageband settings, despite the Media Library window listing all the instrument names. I've also done both a spotlight and manual search on the hard drive to see if I can see where they've been installed - but had no luck with this either.

Anyone able to help?

Thanks