PB 11.5.1.4011, XP sp3

I have a word document (I use word 2002) with the normal .doc extension.
rte_1.insertdocument( "file.doc",true ) --> returns 1 but nothing is
imported ( control remains blank)
If I use the 2d syntax :
ll = rte_1.insertdocument( "file.doc",true,FileTypeDoc! ) --> returns 1
but now it works !!!
Is it a documentation bug, or am I missing something ?
Thanks
Philip