Error changing the cardinality for type I attribute

Hi everyone,

Iam new to dynpro.Iam facing 2 issue while creating a simple application -

1)I have created a node with 2 attributes type I.Now when i try to change the Cardinality from 1..1 to 0..1 it is throwing an error.If i execute with 1..1 it is working fine.

Error description-ERROR: Error in INPUT_FIELD “L1″ of view “YDEV.MAIN”: Context binding of property VALUE cannot be resolved: Node MAIN.1.DISPLAY does not contain any elements (termination: RABAX_STATE)

2)It is not allowing to change the attribute type from I to C for cardinality 1...1.

Error: Type C cannot be instantiated.

Can you please help me to understand the reason for above 2 issues.

Regards,

P D