Using SSAS in BIDS, you need to remember that you should be using MDX instead of T-SQL when designing Calculated Members. Here is an example of how both would be used to prevent a divide by zero error.

T-SQL
-- Comment Block
CASE WHEN [Measures].[Measure2] = 0 THEN 0
ELSE [Measures].[Measure1] / [Measures].[Measure2]
END

MDX
// Comment Block
IIF([Measures].[Measure2] = 0, 0, [Measures].[Measure1] / [Measures].[Measure2])

Both will work, but the T-SQL one will give you some warnings. It’s best to remember to use MDX instead.