Tried to compile a list of things that seem wrong ... did I miss anything?
Errata suggestions
Dragonrider Armor - This has no increase in cost over regular scale. It should be level 12+ if not level 13+. Also as an interrupt it can't be used on your own turn ... is this intentional?
Impaling Weapon - Should be a free action to use. Immediate reaction makes this very hard to use.
Mind-Rending Weapon - Should be a free action to use. Immediate reaction makes this very hard to use.
Symbol of Courage - it's language should be more like fortified armor stating that the effect only works when the effect allows a save
Symbol of the Dragon - This lists as level 3+, but is only priced at 13+
Rog of Baleful Geas - Lists as 11+ but min level is 12. The power is very very strong for the cost. As a free action without limitations it can be used even on opponents turns. It should probably be a minor action?
Bracers of Escape - Level 7 version is nice, higher level versions cost a lot more for a fairly small increase in benefit (not sure how this might be fixed)
Eyes of the Dragon - This item is very similar to the Ioun stone of true sight, but it's five levels lower. Maybe this should be in the level 26 range?
Ring of Draconic Zeal - A free action with no restrictions is strong, not quite sure how this can be fully exploited with a basic attack, but I'm betting there are some strong combos with this item. Perhaps limit its use to after an attack to limit it?
Ring of the Ghost Night - The attack bonus seems too high.
Flask of the Dragon Breath - The attack needs to state what defense it attacks (Reflex?) Again the attack bonus seems high.