Custom appRain application upgrade / troubleshooting CONSULTATION

THIS IS FOR A CONSULTATION / QUOTE ONLY. This problem will need looking at before a quote can be made, and I understand that. Once the candidate has had a chance to look into the problem, they can quote a price to fix it and if accepted, another project can be posted here for a fixed price. Older appRain website isn't running on a new server. Can't move it back to the old one due to a crash. Need someone to upgrade appRain (if possible) and troubleshoot / upgrade existing custom shopping cart app. Original developer has disappeared and will not be available.