On the first iteration you set lastInt to anotherInt. lastInt->nextNode is presumably a null or invalid pointer. Then, rather than storing fileInt (which by the way the loop doesn't even touch, nor does it touch intInputFile) in lastInt->intValue, you move lastInt to the next node, which isn't guaranteed to exist, and assign to that the integer.
- anotherInt gets created. (line 21)
- intLast gets set to anotherInt (line 24)
- lastInt gets set to anotherInt (line 25)
- lastInt gets set to anotherInt->nextNode (line 31 -- PROBLEM)
This is a problem because you never initialized anotherInt->nextNode. Depending on what you're doing in intNode's constructor, you're either dereferencing a null pointer (bad), or dereferencing an uninitialized pointer (worse). Each have potential to crash.
It seems to me that line 31 should be inside the else clause.