Hello!
Anyway, I am not familiar with the particular script, so here are some question to get somewhat better picture:
1) Is this "script" built on core php or is built on some php framework instead (zend, cake, smarty ans the like)?
2) Does the script require some encoding/decoding (like ioncube and the like) to run?
3) What are the exact php versions currently having on local and the live hosts?
4) What is the live server OS and how it's managed - whm/cpanel, plesk, directadmin, other and are the apache and myslq servers one and the same phisycal machine?
5) What is the extent of the modding that was done to the original script?
Now, just a quick comment on your "say you can do and not paying for failure" remarks. First of all, nobody has seen the script neither on your local not on the live host and you have not presented here in detail no substantial information to allow one to make such a judgement, and upon accepting the project we are paying the fee immediately, so we too need to have a certain minimal degree of certainty before embarking on your mission, so to spare the back-forth motion and the frustration I think it would be best if you can provide the script for examination. If I can install it locally and having the answers of the above then it will be certain if I can or not.
Until I am familiar with the script trying to debug it on the live host directly is not a good way to approach it at all.
Let me know if you can provide that.
Regards,
Dobri