Troubleshoot CodeIgniter Production Script

Purchased code from CodeCanyon which uses CodeIgniter as a base. Having some small issues getting it running -- Initially had some database errors, but have resolved all of those. Now getting a fatal call error on the home page. I've done some reading on Stack Overflow, but suspect the issue may be a CodeIgniter issue. If so, I don't have much experience with that framework. This should be a rather straightforward troubleshooting job, as the code has good reviews and clearly works for other people. Looking someone with CI experience who is available to take a look now. Reasonable bids only, all others will be ignored. In exchange, you'll get prompt payment and potential for future projects. Thank you.