Is this a partial cut and paste of your spell or the whole thing?
As an example, let's look at the "Aid" spell (first spell) in CoreSpells.xml
<SpellDef InternalName="Aid">
<DisplayName>Aid</DisplayName>
<Description>Heals target unit by 4 (+2 per life shard).</Description>
<FormattedDescription>Heals target unit by %d.</FormattedDescription>
<Image>T_Heal_Painting.png</Image>
<IconFG>T_Aid_Icon.png</IconFG>
<IconColor>174,255,59</IconColor>
<AutoUnlock>0</AutoUnlock>
<SpellBookSortCategory>Unit</SpellBookSortCategory>
<SpellBookSortSubCategory>Heal</SpellBookSortSubCategory>
<SpellType>Tactical</SpellType>
<SpellClass>Defensive</SpellClass>
<SpellSubClass>Heal</SpellSubClass>
<SpellTargetType>FriendlyUnit</SpellTargetType>
<SpellResourceCost>
<Resource>Mana</Resource>
<Amount>8</Amount>
</SpellResourceCost>
<GameModifier>
<ModType>Unit</ModType>
<Attribute>CurHealth</Attribute>
<IsForFormattedDescription>1</IsForFormattedDescription>
<Calculate InternalName="Calc" ValueOwner="CastingUnit">
<Expression><![CDATA[[UnitOwner_GetNumLifeShards] * 2]]></Expression>
</Calculate>
<Calculate InternalName="Value">
<Expression><![CDATA[[Calc] + 4]]></Expression>
</Calculate>
<Calculate InternalName="ValueForFormattedDescription">
<Expression><![CDATA[[Calc] + 4]]></Expression>
</Calculate>
</GameModifier>
<AIData AIPersonality="AI_General">
<AIPriority>15</AIPriority>
<ValueCalcWrapper>
<ValueType>IsTargetWorthy</ValueType>
<Calculate InternalName="Calc" ValueOwner="TargetUnit">
<Expression><![CDATA[[Unit_GetHPCurrent]]]></Expression>
</Calculate>
<Calculate InternalName="Value">
<Expression><![CDATA[[Calc] < 30]]></Expression>
</Calculate>
</ValueCalcWrapper>
</AIData>
<HitSoundFX>Spell_Heal_01</HitSoundFX>
<HitSoundFX>Spell_Heal_02</HitSoundFX>
<SpellDefEffect>
<EffectName>T_Heal_Particle</EffectName>
<LocalPosition>0,0,0</LocalPosition>
<EffectScale>.75</EffectScale>
<EffectDelay>0</EffectDelay>
<SnapToTerrain>1</SnapToTerrain>
</SpellDefEffect>
</SpellDef>
Note that it has an InternalName, a DisplayName, Icon designation, etc.
Also, (and I'm sure this is a cut and paste issue) be sure the formatting of indentation is correct and lines up and every open has a close.