OK, mostly fixed now. I deleted Frodoplayer and installed the new 1.10 version. Then when I added the new skin it seems to work OK.
This now highlights a problem I'd hidden a long time back & has re-occurred. Some time in the past I changed all the speech to a nonsense word (don't know why now). Now, even though the speech text in the setting pane has valid text FP still says the nonsense words instead. Where is this text stored so I can change it?