help with extension tubes

[magmac21]

I have just recieved a set of extension tubes having never used them before and am not sure if I am doing something wrong . I have attached them to the camera body and got the lens on but the aperture is coming up as 00 in manual mode. This is the same in any any mode . The shutter speed changes. Is this just something that happens with extension tubes?? or am I doing something really obiously wrong?
They are working brilliantly and Im amazed at how close you can get but am having a little trouble trouble with dof but have read on previous threads that this is normal.
If anyone can shed any light on this I will be very grateful.

[gasrocks]

The 000 just means the lens is not talking to the camera as far as aperature goes. They do make manual (vs. automatic) extension tubes. Perhaps this is what you have.