Any precedent for the word "storn"?
Solution 1:
Playing with incorrect application of grammatical rules is a common feature of hacker culture, from which the language Brainfuck also derives: see the introduction to the Jargon File which documents this language. Other examples include using boxen as the plural of box and Unices instead of Unixes (the latter from Latin).
Storn could be by analogy with other past participles ending in orn such as worn and born, although it's not a perfect match (wear, bear vs store? Not quite). So it might just be a typo.