html to prolog mode in XEmacs

[Paulo Henrique Baptista de Oliveira]

        Hi Debian users,
        anyone knows why when I open a .html file in XEmacs and it enters in
html mode, if I press Tab key XEmacs enters in prolog mode?
        Thanks for any help,            Paulo Henrique
        PS: I'm using an older potato (2 months without update, because glibc2.1
and SOffice and xemacs 20.4