Uh, yes I imagine it would. You have a ton of other stuff the ability doesn't know what to do with.
WeaponType "Beam"
damageEnums
AttackType "ANTIHEAVY"
DamageAffectType "AFFECTS_SHIELDS_AND_HULL"
DamageApplyType "BACKLOADED"
DamageType "ENERGY"
WeaponClassType "BEAM"
DamagePerBank:FRONT 1250.000000
DamagePerBank:BACK 0.000000
DamagePerBank:LEFT 0.000000
DamagePerBank:RIGHT 0.000000
Range 6500.000000
PreBuffCooldownTime 10.000000
CanFireAtFighter FALSE
SynchronizedTargeting FALSE
PointStaggerDelay 1.300000
TravelSpeed 0.000000
Duration 1.000000
fireConstraintType "Research"
researchPrerequisites
NumResearchPrerequisites 1
You notice the original ability had no damage information. You are just defining the weapon effect in abilities, any damage they do you define in the buff file. You cannot just paste everything from a ship's weapon and have it work as an ability.
The Vulkoras Desolator's dinintegration ability uses a beam, and it might be a better base to work from.
Alternatively, if you just wanted the ability to apply an extra effect when a ship fires a particular weapon, look at the Marza's Incendiary shells ability. That can be neater in many cases.
Also, we have a thread for just such questions here. If you are posting large amounts of code, pastebin can make things a lot easier on everyone.