Custom converters in Scallop library

I am trying to use Scallop (http://ift.tt/1OUygcy) to parse the command-line arguments in Scala.

However, I cannot compile the example for converting arguments to a case class as shown on http://ift.tt/1UbUKot.

I get two errors at compile-time:

[error]  found   : org.rogach.scallop.ValueConverter[center.scala.sbk.Commands.Person]{val nameRgx: scala.util.matching.Regex; val phoneRgx: scala.util.matching.Regex}
[error]  required: String
[error] Error occurred in an application involving default arguments.
[error]     val person = opt[Person](personConverter)
[error]                              ^

and

[error] ...: could not find implicit value for parameter conv: org.rogach.scallop.ValueConverter[center.scala.sbk.Commands.Person]
[error] Error occurred in an application involving default arguments.
[error]     val person = opt[Person](personConverter)
[error]                             ^

Thank you for your help!