Debian Update issue

[Björn Djisktra <amailuser.14@gmail.com>]

This is the question: I downloaded Firefox and installed it, because
Icewesel can't open a web page. It tell me that I need to upgrade the
browser. But when I run Firefox occurs an error, the prompt tells me:

firefox: symbol lookup error: /opt/firefox32/libxul.so: undefined
symbol: gtk_widget_set_can_focus

This is why I just trying to update the system, because the problem is
with the outdated libraries. So, I need your help with this in order
to solve this issue. Thanks.