[R] R CMD SHLIB errors

[sun]

I got errors when I tried to compile my code into dll on XP box.

"C:/R/R-2.6.2/src/gnuwin32/MkRules:235: warning: overriding commands for 
target `.c.d'
C:/R/R-2.6.2/src/gnuwin32/MkRules:223: warning: ignoring old commands for 
target `.c.d'
C:/R/R-2.6.2/src/gnuwin32/MkRules:255: warning: overriding commands for 
target `.c.o'
C:/R/R-2.6.2/src/gnuwin32/MkRules:243: warning: ignoring old commands for 
target `.c.o'
mingw32-make: *** No rule to make target `''.o', needed by `'''.  Stop."

So I decide to try the example in "writing R extensions" c++ code example 
x.hh,x.cc and xmain.cc, I compiled with "r cmd shlib x.cc xmain.cc" and got 
the same error output:
 "mingw32-make: *** No rule to make target `x.cc''.  Stop."

I was able to compile dll before, since then I have updated R, installed 
other softwares, so I am a bit confusing at this moment what would be the 
cause of this problem. Could some please give some suggestions?  Thanks in 
advance.

Sun