I have also posted this in the wizards class section to see if any other wizards might have experienced this problem. However, after looking into it a bit more myself, I am starting to think it MAY be a bug... but will see what comes out of posting it here...

First things first.

My char level is 18 ( used another char L12 to test an idea on )

I have all required feats and more ( I would think )

I have greater spell focus enchantment
mental toughness
improved mental toughness as well as other metamagic feats

for enhancments:

I took Wizards Energy of the scholar I and II
Improved Concentration I and II
Wizards INT I
as well as a few more to bring me to 16 APs.

with that one would assume that I should be able to take archmage, however I cannot. it is grayed out and I can only see it when I select " show unavailable "

I tested an Idea but using my L12 Rogue/wizzy multiclass 9/3 at the moment plenty good enough to mess around with the enhancements...

Iswapped a feat or 2 to let me test this. I took the spell focus and mental toughness feats. Redid my enhancements.

I made sure I had spell focus ( not greater just plain spell focus )
made sure I had mental toughness ( not improved or anything just the basic mental toughness )

made sure I had improved concentration II, Wizards energy of the scholar II, and Wizards INT I.

guess what folks, it worked...

only think I can surmise is that there is some issue with greater spell focus over plain L1 spell focus... and that it might very well be a bug...

Thoughts / suggestions anyone?

thanks for listening and I will be awaiting feedback / support...