@John, I wasn't aware of the memberprofiles module before, so I won't be able to advise you there. I would suggest contacting the developer of memberprofiles with your issues.
Cannot thank you enough for finding that one out, Andre. Seems to have solved the problems I had!
EDIT: How rude of me, I should of course extend my greatest gratitude to Marijn for creating the module in the first place. Thank you so much for this, it is of great help.