"Conflicting definitions"?

[Duncan Murdoch <dmurdoch@pair.com>]

I'm getting an error message that I don't understand.  Can anyone
help?

I have an abstract class called "orientation", with various
descendants that can be instantiated.   I declare a "%*%" method for
this class, because one way of looking at it is as a list of matrices.
However, I get the following error message:

> setClass("orientation")
> setMethod("%*%", c("orientation", "orientation"), function(x, y, ...)
{
}
)
redefining function "%*%" to be a generic function on database
"F:\Program
        files\Insightful\splus61\users\murdoch"
Warning messages:
  Conflicting definitions of "%*%" on databases "F:\Program
        files\Insightful\splus61\users\murdoch" and  "splus" in:
assign(f,
        what@genericDef, where = where)

(I left the body of the method definition out, to make this post
shorter.)

What does the "conflicting definitions" warning mean?  How should I do
things differently to get rid of it?

Duncan Murdoch