Searching AFP voulmes with ACL’s on some clients crashes Finder – local issue?

Hi guys, I have employed ACL's here on the file server but since then 2 guys out of our 70 users cannot search the AFP shares. When they do there Finders crash. Now I can search the AFP volumes using my Mac & their details, & when using their mac with my details it crashes the same as they get. So obviously this is a local issue, both troublesome macs are intel & so is mine. We're all running 10.4.11 too.. so where to check? Ta! Ben. Please see https://www.afp548.com/forum/viewtopic.php?showtopic=15888&lastpost=true#18709 for more info.