You actually have two errors, and both are going to be dependant on the lines of code where it is failing.
First error is usually due to the fact it used to be a string and now it is either a struct or an array. So you will need to look at that line of code and work it out.
The second is very clear, it is saying that the root is not defined. So again you will need to look at the line of code where it is falling over and find out why or what is using root and why it is not defined.
Now if any of these are due to changes from CB 2.6.3 to CB 3.0 then you will need to go into the Wiki and look at the migration or deprecated things, to see if any of these affect your application.