I FOUND THE SOLUTION!
In order to get past this crash you must have Roy as a Lord. Simple fix, just need a game shark code, do the following:
Enable the following code to make Roy into a Lord, you can have this take effect when you're about to take the throne. I simple rescued Roy and dropped him off and boom! He became a Lord:
8202AB7C A130
After the non-crashed cutsceen, delete the first cheat, and use one of the following codes to change Roy into the desired class of choice:
8202AB7C ####
Replace #### with class of choosing:
A130: Lord
A178: Mercenary M
A1C0: Mercenary F
A208: Hero M
A250: Hero F
A298: Myrmidon M
A2E0: Myrmidon F
A328: Sword Master M
A370: Sword Master F
A3B8: Fighter
A400: Warrior
A448: Armour Knight M
A490: Armour Knight F
A4D8: General M
A520: General F
A568: Archer M
A5B0: Archer F
A5F8: Sniper M
A640: Sniper F
A688: Priest M
A6D0: Priest F
A718: Bishop M
A760: Bishop F
A7A8: Mage M
A7F0: Mage F
A838: Sage M
A880: Sage F
A8C8: Shaman M
A910: Shaman F
A958: Druid M
A9A0: Druid F
A9E8: Cavalier M
AA30: Cavalier F
AA78: Paladin M
AAC0: Paladin F
AB08: Troubadour
AB50: Valkyrie
AB98: Nomad M
ABE0: Nomad F
AC28: Nomadic Trooper M
AC70: Nomadic Trooper F
ACB8: Pegasus Knight
AD00: Falcoknight
AD48: Dragon Knight M
AD90: Dragon Knight F
ADD8: Dragon Master M
AE20: Dragon Master F
AE68: Soldier
AEB0: Bandit
AEF8: Pirate
AF40: Berserker
AF88: Thief M
AFD0: Thief F
B018: Bard
B060: Dancer
B0A8: Makute M
B0F0: Makute F
B180: Divine Dragon
B1C8: Dark Dragon
B210: King
B258: Citizen M
B2A0: Citizen F
B2E8: Children M
B330: Children F
B378: Transport Unit
B3C0: Master Lord
Source: http://www.neoseeker.com/fireemblem-gba/faqs/101446-fire-emblem-6-cb.html
This however will keep the weapon level's the same. To change this use the other codes found in the source.