Spellsword is a full BAB class.On review, I don't see how this class combination is possible.
Paladin(2) BAB +2
Sorceror(4) BAB +2
Spellsword(1) BAB +0
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TOTAL LEVEL 7 / TOTAL BAB +4
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Maximum class skill rank(lvl7): lvl +3 = 10
Maximum cross class skill rank(lvl7): (lvl +3)/2 = 5
Knowledge (the planes) is a cross class skill for sorceror, paladin and spellsword.
Knowledge (the planes) is a cross class skill for sorceror, paladin and spellsword.
Sacred Exorcist: requires Knowledge (the planes) 10 Ranks
However, seeing as Knowledge (the planes) is also a cross class skill for Abjurant Champion, you will have to wait until level 17 before you have enough ranks to consider entering Sacred Exorcist.
Spellsword is a full BAB class.
Knowledge Devotion.
Well, you can always find variant classes to suit your needs.
http://www.crystalkeep.com/d20/rules/DnD3.5Index-Classes-Base.pdf
On p. 83 in there, it has a Paladin variant, Hunter of Fiends, originally from dragon magazine #349. Basically, it's a Paladin more dedicated to fighting evil outsiders. You lose Smite Evil and Knowledge (nobility) and gain Favored Enemy (evil outsiders), with a bonus equal to half your paladin level, the Track feat, and the all important Knowledge (the planes) as a class skill.
EDIT: Oh, and Survival. Track wouldn't be very useful without it.
So, as a rough outline, you'd be looking at something like:
Fighter2/Bard3/(Battle)Sorceror15
as a viable take on this build?
Cheers.
DRACONIC HERITAGE
You have greater connection with your distant draconic bloodline.
Prerequisite: Sorcerer level 1st.
Does this mean i can only take it at creation, or only when I take my first level of Sorcerer?
So, as a rough outline, you'd be looking at something like:
Fighter2/Bard3/(Battle)Sorceror15
as a viable take on this build?
Cheers.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.