I believe your poison is currently declared after the breath attack that is supposed to use it, and the name doesn't match the name used in the breath attack declaration.
Try:
material declaration
[USE_MATERIAL_TEMPLATE:BOG_POISON:CREATURE_EXTRACT_TEMPLATE]
[STATE_NAME:ALL_SOLID:frozen bog spittere spit]
[STATE_ADJ:ALL_SOLID:frozen bog spittere spit]
[STATE_NAME:LIQUID:bog spittere spit]
[STATE_ADJ:LIQUID:bog spittere spit]
[STATE_NAME:GAS:boiling bog spittere spit]
[STATE_ADJ:GAS:boiling bog spittere spit]
[PREFIX:NONE]
[SYNDROME]
[SYN_NAME:bog spitter toxin]
[SYN_AFFECTED_CLASS:GENERAL_POISON]
[SYN_IMMUNE_CREATURE:BOG_SPITTER:ALL]
[SYN_CONTACT]
[CE_NAUSEA:SEV:5:PROB:3:RESISTABLE:SIZE_DILUTES:START:100:PEAK:150:END:200]
[CE_PAIN:SEV:70:PROB:10:RESISTABLE:SIZE_DILUTES:START:1:PEAK:5:END:10]
[CE_NUMBNESS:SEV:100:PROB:1:RESISTABLE:SIZE_DILUTES:START:1:PEAK:20:END:300]
breath attack declaration
[MATERIAL_BREATH_ATTACK:LOCAL_CREATURE_MAT:BOG_POISON:UNDIRECTED_VAPOR]
Instead of:
[MATERIAL_BREATH_ATTACK:LOCAL_CREATURE_MAT:BOG_SPITTER_SPIT:UNDIRECTED_VAPOR]
[USE_MATERIAL_TEMPLATE:POISON:CREATURE_EXTRACT_TEMPLATE]
[STATE_NAME:ALL_SOLID:frozen bog spittere spit]
[STATE_ADJ:ALL_SOLID:frozen bog spittere spit]
[STATE_NAME:LIQUID:bog spittere spit]
[STATE_ADJ:LIQUID:bog spittere spit]
[STATE_NAME:GAS:boiling bog spittere spit]
[STATE_ADJ:GAS:boiling bog spittere spit]
[PREFIX:NONE]
[SYNDROME]
[SYN_NAME:bog spitter toxin]
[SYN_AFFECTED_CLASS:GENERAL_POISON]
[SYN_IMMUNE_CREATURE:BOG_SPITTER:ALL]
[SYN_CONTACT]
[CE_NAUSEA:SEV:5:PROB:3:RESISTABLE:SIZE_DILUTES:START:100:PEAK:150:END:200]
[CE_PAIN:SEV:70:PROB:10:RESISTABLE:SIZE_DILUTES:START:1:PEAK:5:END:10]
[CE_NUMBNESS:SEV:100:PROB:1:RESISTABLE:SIZE_DILUTES:START:1:PEAK:20:END:300]