Error When Loading RStudio Script

I'm trying to debug a section of my code from a larger RStudio script. When I insert just the section of code into its own script and try to load it, an error appears that references a function that doesn't exist in the script I'm trying to load. I've restarted RStudio, erased my RStudio workspace, rebooted my computer and still get the error. Here's the script.

library(shiny)

# Define UI
ui <- (fluidPage
       (
         fileInput("sessionFileName", "Session File Name")
       )
)

# Define server logic
server <- (function(input, output, session)
{
  
  inputParameters <- reactive ({
    if (is.null(input$sessionFileName)) return
    inFile <- input$sessionFileName
    if (!is.null(inFile)) {
      inputData <- readRDS(file=inFile$name)
    }
    inputIDs      <- names(inputData) 
    inputvalues   <- unlist(inputData) 
    for (i in 1:length(inputData)) {
      print (paste(inputIDs[i],inputvalues[[i]],sep=' '))
      session$sendInputMessage(inputIDs[i],  list(value=inputvalues[[i]]) )
    }
  })
})
  
# Start the shiny app
shinyApp(ui = ui, server = server)