I had the same problem when I upgraded from DNN 3.2.1 to 4.5.5.
If you open in the 4.04.00 SQL DataProvider file using a text editer, and hit ctrl F the find box should pop up. Type in HelpURL and hit find. You should come up with the line that is causing the problem. I don't know why this error happens but the following code fixed my problem
SET QUOTED_IDENTIFIER ON
GO
SET ANSI_NULLS ON
GO
ALTER PROCEDURE {databaseOwner}{objectQualifier}GetSearchModules
@PortalID int
as
select M.ModuleID,
M.ModuleDefID,
M.ModuleTitle,
M.AllTabs,
M.IsDeleted,
M.InheritViewPermissions,
M.Header,
M.Footer,
M.StartDate,
M.EndDate,
M.PortalID,
TM.TabModuleId,
TM.TabId,
TM.PaneName,
TM.ModuleOrder,
TM.CacheTime,
TM.Alignment,
TM.Color,
TM.Border,
TM.Visibility,
TM.ContainerSrc,
TM.DisplayTitle,
TM.DisplayPrint,
TM.DisplaySyndicate,
'IconFile' = case when F.FileName is null then TM.IconFile else F.Folder + F.FileName end,
DM.*,
MC.ModuleControlId,
MC.ControlSrc,
MC.ControlType,
MC.ControlTitle,
MC.HelpURL
from {objectQualifier}Modules M
inner join {objectQualifier}TabModules TM on M.ModuleId = TM.ModuleId
inner join {objectQualifier}Tabs T on TM.TabId = T.TabId
inner join {objectQualifier}ModuleDefinitions MD on M.ModuleDefId = MD.ModuleDefId
inner join {objectQualifier}DesktopModules DM on MD.DesktopModuleId = DM.DesktopModuleId
inner join {objectQualifier}ModuleControls MC on MD.ModuleDefId = MC.ModuleDefId
left outer join {objectQualifier}Files F on TM.IconFile = 'fileid=' + convert(varchar,F.FileID)
where M.IsDeleted = 0
and T.IsDeleted = 0
and ControlKey is null
and DM.IsAdmin = 0
and (DM.SupportedFeatures & 2 = 2)
and (T.EndDate > GETDATE() or T.EndDate IS NULL)
and (T.StartDate < GETDATE() or T.StartDate IS NULL)
and (M.StartDate < GETDATE() or M.StartDate IS NULL)
and (M.EndDate > GETDATE() or M.EndDate IS NULL)
and (NOT (DM.BusinessControllerClass IS NULL))
and (T.PortalID = @PortalID OR (T.PortalID IS NULL AND @PortalID Is NULL))
order by TM.ModuleOrder
GO
SET QUOTED_IDENTIFIER OFF
GO
SET ANSI_NULLS ON
GO
Go to the host menu under SQL and run this code as script
Hope this helps
Mike