Pointers to closest portals don’t show up

Since 2013-02-22 new portals are added on Friday around 2AM UTC every 1-3 weeks.
I think they add new portals once in a few weeks at no specific time.

First time they added new portals was ~2012-12-18, Source
Second time it was ~2012-12-26, source
Third time ~2013-01-25, source1 source2
Fourth time ~2013-01-30, source1 source2
Fifth time ~2013-02-22, Source
Sixth time ~2013-03-01, Source1 Source2
Seventh time ~2013-03-22, Source
Eighth time ~2013-03-29

Maybe if we see more new portal aditions around Tuesday-Wednesday we can make assumtion that new portals appear in a middle of a week.
[edit]:It seems that portals are added mostly in a middle of the week, Tuesday-Friday.

Althought Niantic Labs employee said recently that they have a new system for adding portals and its going to be much faster. So maybe things will not be the same after 2013-02-17 and maybe new portals be on Fridays.

Btw it was only 3 times they were added after 2013-02-22, so my answer is not 100% accurate.

You can only use XMP bursters of your level or lower, so for you that's Level 1 bursters.

What do you mean it won't "allow" you to use the XMP?

There are two ways to fire XMP. From the inventory menu, select "Fire" while viewing one of your XMP bursters. The second, and to me the easiest way, is to long-press on the scanner screen and then tap the "Fire XMP" menu option that appears. This will automatically fire the highest-level XMP burster you have access to.

Note as well that you have to have some XM to fire an XMP. If you've been hacking enemy portals and they've been hitting you in response, you may have run out of XM. Also Level 1 XMP are very weak; you should be standing on top of a resonator in order to destroy it, and even then it will probably take more than one XMP.