I've had this happen with SuperBlade Pro on numerous occasions, in Paint Shop Pro 7 - 9. I don't know why it happens. But un-installing the plugin, re-downloading it and unlocking it again fixes it usually.

SFX

NB. This (the image not being transformed although the preview shows the transformation) also happens when the image is too large. Quitting the programme, and re-sizing the picture before applying the affect is the answer to that one.