A bug in v184.108.40.2068 assumes that "Remote File or Folder" must be a Folder, at-least where "Local File or Folder" is a wildcard "C:\...\*". Thus you cannot substitute Scheduler's System Variables here. This may not apply to a static filename?
Until SolarWinds acknowledge and fix this bug, then my work-around was a routine Script for a custom watched Folder that moves files into Voyager's watched folder whilst renaming them. Be aware of User Permissions. I used VBScript, but you could use a Batch file:
for %%F in ("%SOURCE_PATH%\*") do call :1 "%%F"
::: If locked then Move aborts
if not exist "%TARGET_FILE%" move "%~1" "%TARGET_FILE%"