Migrating and upgrading

[judeabb]

I've migrated an installation of AbanteCart 1.2.8 to a new server where I have installed 1.3.2.
The frontend works fine (amazingly) but I can't access the backend and get all manner of critical errors, some of which I can address and others I can't.
Currently the login page loads but won't accept my details (which are correct) and won't send me the password reset email.

Have I made a critical error, by migrating to a newer version of AbanteCart?
What should I do?

Someone on Fiverr reckons to be able to fix it for 180 dollars but wants access to my both Control Panels. I sent him all the relevant files (databases, backups etc.) but am a bit reluctant to let him loose on my whole Control Panel.

Does anyone have any thoughts or suggestions as to the best way to proceed?

Thanks in advance.

Jude

[Basara]

Hello.
A good start is checking your AbanteCart error log