303789 error message when updating maps

[nisa]

'303789' is not a valid value for 'value'. 'value' should be between 'minimum' and 'maximum'.
File: map_fprt_sewer_epic03.dds
at System.Windows.Forms.ProgressBar.set_Value(Int32 value)
at WindowsApplication7.Form1.dlw_ProgressChanged(DownloadWorker& sender)
at WindowsApplication7.DownloadWorker.DownloadFile()

This is the error message I get when trying to update maps.