Conversion error

I am trying to retrieve the tax ID number from the vendor table. I see the field I need, but it comes up blank. All I need is the vendor and tax ID to show up in this query, and all I can get is the Vendor ID and name to show. I tried linking the location table, but I get the following error: conversion failed when converting the nvarchar value ‘Main” to data type integer. I feel like this should be a simple query, but I am obviously missing something.