I'm sure I read in the manual when I recently installed my PicassoIV that if you have any monitor driver other then PAL or NTSC in Devs:Monitors then you will have problems booting into Workbench the first time, this is something you should check.
The PicassioIV has a Video slot Scan Doiubler so should be able to display both native and RTG screens on your Monitor, I guess if worst comes to worst you'll have to install using another screen but if this is the case then maybe some of the software you run (i.e games that use Native screens) may also give you 'out of sync'
Steve.
