HI,
some suggestions.
are you using Cronus standard page or customized page ?
Usually you can't write data in a blocked field or in not visible field on page (and on blocked fields on source table)
Add a COMMIT statement after insert Sales Order Header and before insert Order Lines.
Try to replicate this demo sample on Cronus:
blogs.msdn.com/.../extending-page-web-services-and-creating-a-sales-order-again.aspx
Other solution is :
> publish XMLPorts instead of Pages (for Order Header & Lines) and write data compilng XML Ports Nodes\Elements (is not better solution)