Error Message with Deluge Workflow

Error Message with Deluge Workflow

Hello everyone, I have this Deluge script that executes whenever another form is successfully submitted:

insert into New_Site_Assessment
[
City=input.City
Homeowner_Email=input.Homeowner_Email2
Homeowner_Name1=input.Homeowner_Name
Homeowner_Phone_Number=input.Homeowner_Phone_Number
Site_Address_Line_1=input.Site_Address_Line_1
Site_Address_Line_2=input.Site_Address_Line_2
State1=input.State
Status="New"
Survey_Booking_Status=input.Booking_Status
Surveyor=input.Surveyor
Client=input.Client1
Zip_Code=input.Zip_Code
]


Surveyor and Client are both User fields (Client for portal users, Surveyor for users). Whenever I try to test it, I keep getting this message:

Error

Error details:
 Error in executing On Add - On Success script
 Due to invalid expressions insert statement is terminated Line:(1)
 Invalid user name found for Client field Line:(1)

How can I resolve this? Any help would be appreciated. Thank you.