Upgrading from:

NumericalMath`InterpolateRoot`

All the functionality of NumericalMath`InterpolateRoot`is now available in the newly created Function Approximations Package.

To access functionality from the new Function Approximations Package, load FunctionApproximations`:

Version 5.2 << NumericalMath`InterpolateRoot`;
InterpolateRoot[Exp[x] == 2, {x, 0, 1}, WorkingPrecision -> 40]