haaa.... yes indeed, bad Ethernet connection can cause some side-effect.
We developed CopperLan over Ethernet protocol in 2008, since we tried a lot of standard and low-cost Ethernet switch without any problem so far.
So I would tend to think of a cable problem rather than the switch itself. But... maybe you found the switch that is not working with CopperLan... who knows...
My network is currently built around 5 different 8 ports 100Mb/Gb switches from DLink. The last I bought is a D-Link DGS-108 which is quite cheap.
But please check your cables before changing of switch