SSRS Multiple Select and "Select All" Parameter Problem

I have a report which shows the receipt infos. For instance like below

ID        Name               Date            Createtor                Payment Date

1          Bob               12.12.2012           bb                         01.01.2013

2          Smith            15.01.2010           smt                       15.02.2011

3          Peter             21.02.2011           ptr                         

4          Sarah            18.06.2012           srh                         23.07.2012

I have two parameters which I have created by the Query where is in Dataset as below.

SELECT *

FROM vw_receipt_info

WHERE ReceiptDate=@date and creator=@creatorsc

Mine date parameter drop down has year of 2010,2011,2012,2013 and mine creator dropdown parameter has "bb", "smt", "ptr" and "srh".  When I select one year and one creator then it works. However , if I want to select two or more creator and years  or if I select the "Select All" option then it doesn't work and gives me the error mesage below. 

"An error occured during local report processing. An error has occured during report processing. QUery execution failed for dataset 'Dataset1'. Incorrect syntax near ','.