Dcount on multiple criteria

I am using the following code to determine if a record exists in table tmpJobs were week = thisweek and CustomerID = thisCustomerID

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Dim thisCompany As Integer
Dim thisweek As Integer
JobCount = DCount("[Week]", "tmpJobs", "[week] =" & thisweek And "[CompanyID]=" & thisCompany)

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I am getting data mismatch.

If I seperate the line into two

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JobCount = DCount("[Week]", "tmpJobs", "[week] =" & thisweek)
NoJobs = DCount("[Week]", "tmpJobs", "[CompanyID]=" & thisCompany)

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this works and JobCount and NoJobs = 1

Why can't I  have them on same line to only count when both criteria are met.