there was an issue with blob subtype 1 columns incorrectly mapped to be byte, where a string should be mapped. Therefore the mentioned converter gets into the game and fails.
Please change the mapping to string for those columns. The using fields will then be correctly handled by the meta data and the RIA wizard should work again.
the Telerik team
Q1’11 SP1 of Telerik OpenAccess is available for download
; also available is the Q2'11 Roadmap
for Telerik OpenAccess ORM.