Unsolved: Cant step through the presets on my Polar

[robbles]

HI, Can anyone help me with a frustrating problem with my TI Polar. I have lost the ability to step through preset sounds and banks using the PARAMETERS and VALUE keys. Sometimes I can step through two or three presets. Generally either the SEARCH or EDIT LFO screens appear on the display. If I press the Exit key the display returns to the screen showing a patch with an E in front of the patch reference (E ROM-G3 for example). I guess that means that the patch has some edits waiting to be saved? However I cant remove that. I occassionaly see an Last Edit Undone message or a Transpose keyboard. Other than that problem everything else seems OK. I have tried closing down, resetting from the ARP Edit key and installing the latest upgrade but it makes no difference. It is the same in standalone or USB mode.
Rob