Firstly, please update to v4.05.2 Beta -
PT4 Download Page.
Please follow the configuration guide that Kraada linked you to to make sure that the new site software is configured to save hand histories - once you've played a few hands and the files have been written you will be able to browse to (or type in) the hand history path even if auto detect still doesn't find it.
BTW, if auto detect doesn't find it (and the folder exists) please open a
Support Ticket and tell us the default path that Juicy uses and we'll see if we can get that corrected.