JSON parse failing over certain data size

Hi

I'm loading this test object from an external txt file into CS6 using JSON.parse:

{"TEST":[{"Key1":"Val1","Key2":"Val2","Key3":"Val3"},{"Key1":"Val1","K ey2":"Val2","Key3":"Val3"}]}

It works fine, except if I have over about 2500 copies of {"Key1":"Val1","Key2":"Val2","Key3":"Val3"} in the TEST array, then Error #1132: Invalid JSON parse input is triggered.

Anyone know of a datasize limit when parsing JSON?