Cannot resolve collation conflict for equal to operation.

Hi, I have this error when running a query:

Cannot resolve collation conflict for equal to operation.

but the situation is that I can run the query perfectly with one user (windows user) but using an standar user, I've got the error, as far as I know the collation feature applies to db's an objects not to users, what can I do to run this query with the standar user? both users have the same permission on the db. Below is the query attached.

Thank you
Gabriel

SELECT B.EmpSupervisorId, a.Info_ID as A_Info_ID,
ISNULL(a.Owner_SSO_ID,'') as A_Owner_SSO_ID,
ISNULL(a.Ref_SSO_ID,'') as A_Ref_SSO_ID,
ISNULL(a.Prev_Owner_SSO_ID,0) as A_Prev_Owner_SSO_ID,
ISNULL(a.MgmtTypeFlag,0) as A_MgmtTypeFlag,
ISNULL(a.CurrentStatusID, 1) as A_CurrentStatusID,
ISNULL(a.PrevStatusID,0) as A_PrevStatusID,
ISNULL(C.ConTypeOption, '') as C_ConTypeOption,
ISNULL(CAST(a.Last_Status_Update_Date AS VARCHAR),'') as A_Last_Status_Update_Date,
ISNULL(B.sfBUID,'0') as A_Bus_Group_ID, 0 AS A_Bus_Group_Seg_ID,
ISNULL(a.Organization,'') as A_Organization,
ISNULL(a.ContactName,'') as A_ContactName,
ISNULL(A.Title, '') as A_ContactTitle,
ISNULL(a.ContactComName,'') as A_ContactComName, ISNULL(a.Phone,'') as A_Phone,
ISNULL(a.NatureOfOppID,'') as A_NatureOfOppID, ISNULL(a.DealAmount,0) as A_DealAmount, ISNULL(CAST(a.Cust_Contacted_Date AS VARCHAR),'') A_Cust_Contacted_Date, ISNULL(CAST(a.Lead_Qualified_Date AS VARCHAR),'') A_Lead_Qualified_Date, ISNULL(CAST(a.Tran_Processed_Date AS VARCHAR),'') A_Tran_Processed_Date,
ISNULL(CAST(a.Quote_Accepted_Date AS VARCHAR),'') as A_Quote_Accepted_Date,
ISNULL(CAST(a.Approved_By_HFS_Date AS VARCHAR),'') as A_Approved_By_HFS_Date,
ISNULL(CAST(a.Funded_By_HFS_Date AS VARCHAR),'') as A_Funded_By_HFS_Date,
ISNULL(a.Lead_In_Amount,0) as A_Lead_In_Amount,
ISNULL(a.Cust_Contacted_Amount,0) as A_Cust_Contacted_Amount,
ISNULL(a.Lead_Qualified_Amount,0) as A_Lead_Qualified_Amount,
ISNULL(a.Tran_Processed_Amount,0) as A_Tran_Processed_Amount,
ISNULL(a.Quote_Accepted_Amount,0) as A_Quote_Accepted_Amount,
ISNULL(a.Approved_By_HFS_Amount,0) as A_Approved_By_HFS_Amount,
ISNULL(a.Funded_By_HFS_Amount,0) as A_Funded_By_HFS_Amount,
ISNULL(CAST(CreationDate AS VARCHAR),'') as A_CreationDate,
ISNULL(a.BusType,'') as A_BusType,
ISNULL(a.NonHFS_XLink_ContactName,'') as A_NonHFS_XLink_ContactName,
ISNULL(a.NonHFS_XLink_Bus_ID,'0') as A_NonHFS_XLink_Bus_ID,
ISNULL(a.Comments,'') as A_Comments, ISNULL(a.ExistCustomerID,'') as A_ExistCustomerID,
ISNULL(a.FinancialNeedID,'') as A_FinancialNeedID,
ISNULL(a.CampaignID,'') as A_CampaignID,
(GEC_HFS_CORE.dbo.GetBusinessDays(Last_Status_Upda te_Date, getdate())-1) as BusDateDiff, ISNULL(A.DealTypeID, '') as A_DealTypeID
FROM tblInformation a
LEFT OUTER JOIN GEC_HFS_LM_SSOInfo B ON A.Owner_SSO_ID = B.sfSSOID
LEFT OUTER JOIN tblContactType C ON a.Bustype = C.ConType_ID
WHERE a.CurrentStatusID NOT IN (9, 10, 11) AND
ISNULL(a.isNoChange,'NO') = 'NO' AND ISNULL(a.IsDeleted,'NO') = 'NO' AND
DATEDIFF(DAY, Last_Status_Update_Date, GETDATE())<> 0 AND
ISNULL(a.isNonHFS, 'NO') = 'NO'
ORDER BY A_Info_IDAdd COLLATE DATABASE_DEFAULT to character-based comparison operations and forget it.|||It is woking now, tks. Any idea why it is necessary to specify this on one account and not with the other? I wuold like to have something to say to the users.

Tks
GAP|||Here's what I think (it may be too far fetched, but I've seen it):

One of the tables has a twin brother under a different schema, which happens to be the standard login. That twin brother somehow was built using different collation. When that user logs on and runs the query (AND since you do not qualify the tables by schema) the twin brother is picked, thus, - collation errors.