Virtuemart upgrade disastrous

[fmlk4u]

Hello,

After creating a staging copy of the website I tried to upgrade to VM 3.0.14 and got a MySQL error. It appeared and error in $dbtype. After fixing that the errors were so much that I am glad I did it in the staging copy. Any idea what causes this?

[Studio 42]

Parhaps json_encode is not active on your stagging server?
In some linux release, this need to be added manually