merge stuck halfway through a module

hi, 
thanks for the support so far it has been appreciated. with lots of help ive been getting the merge software  going, but ive hit a snag with the merge forums module ....please see attached. as other modules are dependent on this im a bit stuck so any help would be appreciated

ive attached a screen shot 

www.lexus-world.com

mybb : 1.8.30


  Screenshot (91).png (Size: 258.34 KB / Downloads: 9)


  Screenshot (92).png (Size: 242.28 KB / Downloads: 8)

it has merged all of the forums in nicely but its stuck at that point

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every time run it i hit that same error....... but all of the forums have merged over, i just cant get that it to finish that module and all of the others are dependent on it so i cant run thme

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  Screenshot (96).png (Size: 178.52 KB / Downloads: 6)

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any suggestions as to where i can find the solution ? from what i have seen its related to a column having a value or no value but i dont know where else to search