Delete the
document.write(post); line.
And I don't think You need var post to be declared, change it to
mauPostNhac("a:/MERRYC~8.GIF","ROMEO & JULIET","The story...","smoon");
Btw, it's a slash ( \ ) not backslash ( / ), so it's supposed to be
a:\MERRYC~8.GIF.
Oh, and if I visit Your website, there is a 99,99% chance I wont be able to see the image. Why? Because If You declared it as "a:\MERRYC~8.GIF", so My browser will look MERRYC~8.GIF file in My floppy drive :p