no free buffers for rx

Did you use the "reassign base address" option afterwards? It should move all your components addresses again, and hopefully solve the overlap problems.

I see you have an Avalon Clock crossing bridge too, try to lock it to address 0 too if you still have problems. I think it is the one responsible for the last error (ddr2_bot.s1 appears at more than one address).

Also check that you don't have any component with an Avalon Slave interface that is connected to both sides of a pipeline bridge. This could confuse SOPC builder.