It doesn't mean that the pop-up blocker is in use, as the blocker just block the pop-ups, not the persona from appearing in the ComPanel. If he/she appears on the CP, and doesn't answer your grams; that is sign of either that he/she has a block-up blocker, or that his/her CP doesn't refresh correctly (pressing F5 once or twice while CP window activated should fix the latter).

Instead it means, usually, that his or her browser has not javascript (or java) installed or selected (the CP runs on javascript), or he/she has deselected it, so as not to show up online)

To fix this:

If you have Firefox click "Tools", go down the list to "Options" and from there click the tab "Content", and select the "Enable Javascript" (and just in case also "Enable Java"); and Click "Ok".

If you have Internet Explorer, Click "Tools"; go down to "Internet Settings", and there click the tab "More settings"(?), and from the list select the setting for Sun Java (and other java settings). And click "use"-button. (of these IE things I'm a bt vary cause I don't use it much, anymore, and the version I have is still the Finnish language version.

Other browsers must have something similar ways to select to use javascript and java.