Any ideas why this doesn't work?

programming flash
1

ActionScript Code:
[FONT=Courier New][LEFT][COLOR=#000000]var[/COLOR] m1_depth:[COLOR=#0000FF]Number[/COLOR] = [COLOR=#000080]1018571[/COLOR];

[COLOR=#000000]function[/COLOR] attach_mb[COLOR=#000000]([/COLOR]mc_name, mc_inst, xPos, yPos, zdepth[COLOR=#000000])[/COLOR][COLOR=#000000]{[/COLOR]
thisRoot.[COLOR=#0000FF]attachMovie[/COLOR][COLOR=#000000]([/COLOR]mc_name, mc_inst, zdepth[COLOR=#000000])[/COLOR];
mc_inst.[COLOR=#0000FF]_x[/COLOR] = xPos;
mc_inst.[COLOR=#0000FF]_y[/COLOR] = yPos;

wind1.[COLOR=#000080]bt[/COLOR].[COLOR=#0000FF]onPress[/COLOR] = [COLOR=#000000]function[/COLOR]COLOR=#000000[/COLOR][COLOR=#000000]{[/COLOR]
attach_mb[COLOR=#000000]([/COLOR][COLOR=#FF0000]“past_btn”[/COLOR], [COLOR=#FF0000]“past1_btn”[/COLOR], [COLOR=#000080]167[/COLOR], [COLOR=#000080]257[/COLOR], m1_depth[COLOR=#000000])[/COLOR];

[COLOR=#000000]}[/COLOR]
[/LEFT]
[/FONT]

It’s attaching the mc, and it seems as though the depth var is working, but ithe x y coordinates are not. They are gettig placed at 0 x and 0y.
can anyone help? If I can get that to work right I can cut my script in half I think:)
Thank you!