Are you sure you have the latest uboot on device?
Create and build a default uboot project for ccwmx28 using latest DEL 5.9.6.2 and flash onto module to see will it work with 10BaseT .
I am using DEL 5.9.6.2. A new default build of u-boot shows the same problem. Version U-Boot 2009.08 - DUB-1.6.3.1
I see reference in knowledge base article on another u-boot issue that refers to DUB-1.6.4.x - are there updates available to fix these issues or do they all have to be hand patched?