I have a plugin which depends on the other several Dlls. When I put the Dlls in the same folder as my plugin, the photoshop complained it couldnot find the Dlls. So I'm wondering what the the DLL search path for Photoshop? Does it even not include my plugin folder?
You should check the Microsoft web site for details on how DLL's are found. Putting your DLL next to the Photoshop exe is what I would do.
FYI, XP would give you no hint as to why your plug-in wouldn't load. NT would give you a warning dialog (thank you). Win7 also gives you a warning dialog (thank you). But the "thank you" is from a developer perspective. Users don't understand or care about dialogs that complain about missing DLL's. Those users usually call Adobe Tech Support!