(Active) USB extension cables not working on mac?

Hi everybody!
Being a proud owner of a new imac (yep, switching from windows, first time to have a mac) I must admit I really love this stylish piece of hard and software.
No big trouble yet except one really annoying problem:
I bought a 5 m active USB extension cable to connect a printer but I can't get it working! The cable works fine when connecting a printer/ext. hdd/mouse, etc with my windows laptop but the mac does not detect any devices connected via the cable at all. Connecting devices directly to the mac's USB ports works fine, connecting the same devices via the USB extension does not work.
Any ideas? Thanks for the replies!

Does anybody have any experiences with regular (non-active) extension cables? Up to which length do they work?

About 16ft... See:

USB.org - FAQ: Cables, Connectors, and Networking

To the OP:

It all depends on the device being connected and what the load is. I've used USB extension cables (non active) for printers and they work fine. However, the same extension cable attached to an amplified WiFi antenna does not work because of the load.

Also, the plug and play capability of Windows seems to be better at detecting devices than OS X. At least that's been my experience.

Regards.

hmmm... I think it is not a load problem as even a USB stick is not recognized, a mouse or any other device neither...

Then it's likely the cable itself. Is it possible to try another cable?

Regards.

yep! Did this already. Same result. Windows: cables work with all devices. Mac: none of the devices is detected.

5M = 16.4 feet, so you're over the limit.

Try an "inactive" extension cord, and/or a shorter one.

Did you try a powered USB hud.

Yes, I tried. Devices connected via the powered hub to the mac are detected. connecting the hub with the active cable does not work. (Neither mac->short cable->hub->5m cable->device nor the connection mac->5m cable->hub->short cable->device)
I just ordered some non-active USB cables (1,8m, 3m, 5m) on ebay. They are only about 2 EUR, so I can experiment what works and what does not.

Concerning the 5m "over-the-limit" issue: All manufacturers of active 5m cables claim that they should work. This is true for Win as I tested earlier. They work well on any Windows PC/Laptop. Just the mac ignores the devices connected with an active 5m cable.