Multi value error in webi

Hi,

We have 5 Data providers.

Merging on

Plant Id, Vendor Id, Company Code, Doc Id, Line item id, Material Group Id, Material Id

Output on the report

Vendor_Id, Vendor_Name, Plant_Id,Plant_Name, Comp_Id, Comp_Name, Order Date, Rec Date

I am getting multi value error for Order Date, Rec Date.

I have created detail object for order Date, Rec Date associated  with Line Item Id dimension.

Used the following formula for

Order Date=[Order Date] ForEach([Comp_Id];[Plant_Id];[Vendor_Id];[Material Group Id];[Material Id];[Doc Id];[Line Item Id])

Rec Date=[Rec Date] ForEach([Comp_Id];[Plant_Id];[Vendor_Id];[Material Group Id];[Material Id];[Doc Id];[Line Item Id])

We have multiple order Dates, rec Dates For each Line Item

Let me know where is the problem.