Allah is just the Arabic word for God.
http://en.wikipedia.org/wiki/Allah
Arabic speaking Christians use the word, including Greek Orthodox as I ahve heard it used in the liturgy.
Of course it is a bit silly for Dutch speakers to use the word, I might as well call Him "Bog" (slavic) or well I use Dieu (when I speak French) or well "Theos"
Θεός in Greek. I understand what the bishop was trying to do, but I find it silly at best. I would not accept prayers for certain Catholic saints in the Orthdox Church even if I like their writings or admire them...nor do I expect Protestants to honour saints at all.