There r so many reasons behind this issue. I am saying about FF (u usually use) browser, select tools > options > content > uncheck the Disable pop-up windows. To resolve it, just re-enable and conf the pop-up blocker to allow the site, *.ibm.com.
This issue is also cause specially with pop-up blockers for a 3rd party toolbars (yahoo / google toolbar) that run within the browser. Try to temporarily remove the toolbars from ur FF / disabling their pop-up blockers; then re-attempt the same action.