What should I do in an sql case when multiple conditions?

In an sql case when multiple conditions-

,CASE WHEN i.DocValue ='F2' AND c.CondCode IN ('ZPR0','ZT10','Z305') THEN c.CondVal

  ELSE 0 END as Value

There are two types of CASE statement, SIMPLE and SEARCHED.

You cannot evaluate multiple expressions in a Simple case expression, which is what you were attempting to do.

-- Simple CASE expression: 
CASE input_expression 
     WHEN when_expression THEN result_expression [ ...n ] 
     [ ELSE else_result_expression ] 
END 
-- Searched CASE expression:
CASE
     WHEN Boolean_expression THEN result_expression [ ...n ] 
     [ ELSE else_result_expression ] 
END
Example of Simple CASE:
CASE x
  WHEN 'a' THEN 'b'
  WHEN 'c' THEN 'd'
  ELSE 'z'
END
Example of a Searched CASE:
CASE 
  WHEN x = 1 AND y = 2 THEN 'a'
  WHEN x = 2 AND y = 1 THEN 'b'
  ELSE 'z'
END

Further Reading: http://msdn.microsoft.com/en-us/library/ms181765.aspx