Correction and reasons of code problem

Hi all, I have problem with code of Quick Search algorithm as follow: This algorithm works normally when I use long (1024 characters) or short (less than 100 characters) patterns with DNA database (big sizes), but it either is not working or shows wrong results when I use same patterns' lengths with English text and Source code databases. So please if you can help me by correcting and inform me about the reasons of this problem, and to be worked also in English and Source code databases. I already have this code if you need I am ready to send it as soft copy in C language.