One idea that comes to mind is that you're not dropping your object handle to IM_ItemInquiry_ui at the end of your script.

If i remember correctly, each time they click that button, it's is getting a new handle.

One way around this is to store the numeric object handle from GetObject to a variable in your script and then store it in the current bus object's script object or the session's script object using the SetStorageVar method, at the beginning of your script, use whichever script object you choose and use the GetStorageVar method, check if the value is 0, if it is, then this is the first time the button has been clicked and you will need to get the numeric handle and then use the SetStorageVar method so it can be retrieved on future clicks, if not, then use the session AsObject method passing the numeric handle variable you retrieved and "set" it as a vbscript object.

The other way you can do this is real clean and simple. Set the button script to run on the server and put the following in the script file,

Set oLines = oSession.AsObject(oBusObj.Lines)
sItemType = ""
retval = oLines.GetValue("ItemType$", sItemType)
If sItemType = "1" Then
    oUIObj.DRBT_ItemInquiry()
Else
    sretval = oSession.AsObject(oSession.UI).MessageBox("", "Select a valid item to launch Item Inquiry.", "icon=I")
End If
Set oLines = Nothing

Add your desired shortcut key (Hot Key) to your button and you should be good to go.

One idea that comes to mind is that you're not dropping your object handle to IM_ItemInquiry_ui at the end of your script.

If i remember correctly, each time they click that button, it's is getting a new handle.

One way around this is to store the numeric object handle from GetObject to a variable in your script and then store it in the current bus object's script object or the session's script object using the SetStorageVar method, at the beginning of your script, use whichever script object you choose and use the GetStorageVar method, check if the value is 0, if it is, then this is the first time the button has been clicked and you will need to get the numeric handle and then use the SetStorageVar method so it can be retrieved on future clicks, if not, then use the session AsObject method passing the numeric handle variable you retrieved and "set" it as a vbscript object.

The other way you can do this is real clean and simple. Set the button script to run on the server and put the following in the script file,

Set oLines = oSession.AsObject(oBusObj.Lines)
sItemType = ""
retval = oLines.GetValue("ItemType$", sItemType)
If sItemType = "1" Then
    oUIObj.DRBT_ItemInquiry()
Else
    sretval = oSession.AsObject(oSession.UI).MessageBox("", "Select a valid item to launch Item Inquiry.", "icon=I")
End If
Set oLines = Nothing

Add your desired shortcut key (Hot Key) to your button and you should be good to go.