1) Check to see if you have .rootrc. If not you need to copy it like so:
cp $ROOTSYS/etc/system.rootrc and then
$HOME/.
2) cd /usr/local/root/bin
3) Then you need to rename .rootrc so type: mv system.rootrc .rootrc
4) Now you are going to edit .rootrc with the following: vi .rootrc
5) Once you are there (there should be a lot of blue writing), edit the
Browser name by typing / then enter then Browser.Name another thing
should appear which you must change as the error message indicated (aka
change from TRootBrowserLite to TRootBrowser). You can use x to delete,
i to insert and use esc to get out of edit mode and :wq or shift ZZ to save the file. You can use :q! to quit vi if you really messed up your editing so you can start over.
6) Then if you type grep TRootBrowser .rootrc you should be able to see
that the browser name is changed and you can start over again

-Chelsea

1) Check to see if you have .rootrc. If not you need to copy it like so:
cp $ROOTSYS/etc/system.rootrc
2) cd /usr/local/root/bin
3) Then you need to rename .rootrc so type: mv system.rootrc .rootrc
4) Now you are going to edit .rootrc with the following: vi .rootrc
5) Once you are there (there should be a lot of blue writing), edit the Browser name by typing / then enter then Browser.Name. Another thing should appear which you must change as indicated by the error message (aka change from TRootBrowserLite to TRootBrowser). You can use x to delete, i to insert and I think it is either escape or q! to get out.
6) Then if you type grep TRootBrowser .rootrc you should be able to see that the browser name is changed and you can start over again by typing TBrowser b; in root.

-Chelsea

Google says: This

arrggh

So please give some details here:
1) What OS you are using?
2) Which version of ROOT did you download?

Thanks, Arno