Query Criteria Not Working

I have a query with several criteria

SELECT tblProjectDetails.projectid, SubType.SubType, tblProjectDetails.status, tblProjectDetails.product, tblProjectDetails.description, tblProjectDetails.type, tblProjectDetails.producttype, tblProjectDetails.confidence, tblProjectDetails.flatamount, IIf(IsNull([reduction]),(([currentprice]-[newprice])*[volume])/(13-[cutinmonthnmbr]),(([reduction]*[volume])/(13-[cutinmonthnmbr]))) AS Calc, ([flatamount]/(13-[cutinmonthnmbr])) AS Calc2, IIf(1>=[cutinmonthnmbr],IIf(IsNull([flatamount]),[Calc],[Calc2])) AS Jan, IIf(2>=[cutinmonthnmbr],IIf(IsNull([flatamount]),[Calc],[Calc2])) AS Feb, IIf(3>=[cutinmonthnmbr],IIf(IsNull([flatamount]),[Calc],[Calc2])) AS Mar, IIf(4>=[cutinmonthnmbr],IIf(IsNull([flatamount]),[Calc],[Calc2])) AS April, IIf(5>=[cutinmonthnmbr],IIf(IsNull([flatamount]),[Calc],[Calc2])) AS May, IIf(6>=[cutinmonthnmbr],IIf(IsNull([flatamount]),[Calc],[Calc2])) AS June, IIf(7>=[cutinmonthnmbr],IIf(IsNull([flatamount]),[Calc],[Calc2])) AS July, IIf(8>=[cutinmonthnmbr],IIf(IsNull([flatamount]),[Calc],[Calc2])) AS Aug, IIf(9>=[cutinmonthnmbr],IIf(IsNull([flatamount]),[Calc],[Calc2])) AS Sept, IIf(10>=[cutinmonthnmbr],IIf(IsNull([flatamount]),[Calc],[Calc2])) AS Oct, IIf(11>=[cutinmonthnmbr],IIf(IsNull([flatamount]),[Calc],[Calc2])) AS Nov, IIf(12>=[cutinmonthnmbr],IIf(IsNull([flatamount]),[Calc],[Calc2])) AS [Dec], tblProjectDetails.cutinmonth, tblProjectDetails.DMO, tblProjectDetails.fcstloc, tblProjectDetails.projecttype, tblManagers.last, tblManagers.managerid, tblProjectDetails.currentsupplier
FROM tblManagers RIGHT JOIN (SubType RIGHT JOIN tblProjectDetails ON SubType.SubTypeID = tblProjectDetails.subtypeid) ON tblManagers.managerid = tblProjectDetails.managernew
WHERE (((tblProjectDetails.status)<>"Concept" And (tblProjectDetails.status)<>"Tabled") AND ((tblProjectDetails.producttype)<>"3") AND ((tblProjectDetails.confidence)="1") AND ((tblProjectDetails.cutinmonth)<>13) AND ((tblProjectDetails.DMO)<>Yes) AND ((tblProjectDetails.fcstloc) Is Null) AND ((tblProjectDetails.projecttype)<>"Other") AND ((tblProjectDetails.cutinyear)=2006) AND ((tblProjectDetails.currentsupplier)<>"Venture"));

Everything works great except for the very last criteria <> "Venture". I have one project that this query should leave out but it eliminates any project with a Null in the supplier field instead of just supplier "Venture". Why would it do that and what would be the solution?

Thanks

Toni