Debug Payment solution (paylane) - Magento ver. 1.8.0.0

We are using paylane and Magento ver. 1.8.0.0. After paying, appeared "An error occurred in the process of payment” and no order email comfirmation is being sent to customer. However order and payment are being received by our payment solution ok but does not seem to communicate it properly to our magento store. We are looking for someone who can debug this. Experienced applicants only.