The F5 makes it an E Phrygian because the it is the second note of the E Phrygian scale. Basically, phrygian is the third mode of a MAJOR scale...E is the third note of the C Major Scale..This means, with the progression, you could play any note found within the C Major Scale (C D E F G A or B) and it would sound right...however, because of tension in music, it's better for a listeners ears if there is a tone centre...in this case, it'd probably be E, so by targeting or starting off on an E your solos will sound more at rest...
All you do is play the C Major scale, BUT you START from the E..So instead of (C D E F G A B), you play (E F G A B C D)...exactly the same notes, but from a different starting postion...
Take your time, read through this a few times...Modes are difficult AT FIRST, but once you've managed to get your head around it them become the keys to whole new doors in your playing....
Sorry if all I've done is confuse things...

[This message has been edited by Willdridge (edited 07-06-2000).]