Michael,
This is a common problem. Please see my post on this forum dated 7/13/99 - Why aren't my X-10 commands getting through?
One additional piece of information regarding wall switches. The type that you have are very cheap and are not very sensitive to X-10 commands. There are newer, more sensitive switches that may work in your situation without the need for an amplified signal bridge. The only way to tell for sure is to purchase a switch and try it. Even if you still need an amplified signal bridge the new switch is a good investment because it offers other features like soft start and memory dim.
We offer a complete line of home automation products, and excellent technical support with every purchase.
Robert
RCI Automation
rciautomation@csi.com[Link: ourworld.compuserve.com]