clk-pad, ibufg, dcm Problem

Hi,

I have my clk from the pad connected to an ibufg like this:

IBUFG_clk_main: IBUFG port map ( O => clk_main, -- Clock buffer output I => clk -- Clock buffer input (connect directly to top-level ); dcm1_1 : dcm1 port map ( CLKIN_IN => clk_main, RST_IN => RESET, CLK0_OUT => clk_int, LOCKED_OUT => locked, CLKDV_OUT => clk_8m, CLKIN_IBUFG_OUT => open);

at the output of the IBUFG are 2 dcms. Durin NgdBuild I get these errors: ERROR:NgdBuild:455 - logical net 'clk_main' has multiple driver(s): pin O on block IBUFG_clk_main with type IBUFG, pin PAD on block clk_main with type PAD WARNING:NgdBuild:464 - input pad net 'clk_main' drives multiple clock buffers ERROR:NgdBuild:924 - input pad net 'clk_main' is driving non-buffer primitives: pin O on block IBUFG_clk_main with type IBUFG

What do I have to do? Can somebody explain when and where I have to use an extra BUFG?

Thank You.

regards, Benjamin