Update rails to 2.0.2, have some questions

When I update rails from 1.2.6 to 2.0.2.
I got some questions, but I don’t know how to figure out them.

1:undefined method `strip_tags’
there is not function strip_tags() in rails 2.0.2?

2: if I use init_gettext “myweb” in application.rb
I got 500 internal server error

all above is very weird for me. who can help me?