It looks like you have no tags folder created. Is it possible or not? If
so, you have set of options which allows to avoid the problem:
1) You can enter tag name manually (and tags folder will be created
automatically)
2) You can create tags folder manually (in that case "Browse" button will
not show any tags until tags are created)
3) You can disable support of SVN recommended layouts at
Window->Preferences->Team->SVN->Repository->Branch and Tag Settings and in
that case "Browse" buttoon will simply show repository content instead of
tags folder content.