It shouldn't cause any issue BUT......
What is your current version of PCLinuxOS? and is your current FFox the same as the 2010.7 version (i.e. 3.6.
If you have any concerns about doing it for your bookmarks I would suggest installing the xmarks
addon which will sync all your current bookmarks to the new 2010.7 FFox (AND any other PC's you may have if you so wished)
Another addon I like is FEBE
which backups all your addon extensions and another is CLEO
which "packs" all those FEBE "backed-up" addons into one file (like a zip) so when you have a clean FFox its simply a matter of opening the Cleopack file and all the addons are re-installed in one hit.
Whilst were on the subject of addons
worthwhile one is Lastpass
which keeps all your browser passwords encrypted and again can be used - like xmarks - on any PC you use.....