You can't catch many fish without bait!

What did your error message say? I know it is may look meaningless (line number would be), but it usually includes something of a clue about which line failed.

Where did you put this script? Is it an event script or button script?

Is this MAS 90 or 200? Version?

MAS90 v4.50 and it is an event script. I'll post the error later.

If the script were attached to a header field (such as ShipVia) then your context is that of the header and those fields would be referenced using oBusObj and not oHeaderObj. 

Only when you are in the context of the detail line would you use oHeaderObj to refer to a header field.

Dan The Man comes through again. Changed HeaderObj to BusObj and it works. Now I just need to figure out to add 25 days to the date.

If I change the line to:

retVal=oBusObj.SetValue("UDF_HOUSTON_DATE$",sDate+25)

I receive an error message of  Error #26, variable type invalid.

Here is one way that I have done this.

newDate = ""
retVal = oSession.FormatDate(sDate, newDate, "%M/%D/%Y")
newDate = DateAdd("D", 25, newDate)
newDate = oSession.GetFormattedDate(CStr(newDate))
retVal = oBusObj.SetValue("UDF_HOUSTON_DATE$", newDate)

Hey thanks a lot, that works.