Each command line parameter is expected to take up a single 'slot'. Use quotes to enter parameters with spaces in them, e.g.
C:\Program Files\Mythicsoft\Agent Ransack\AgentRansack.exe -o c:\afacts\searchresults.txt -oft -oc -c "judge mangum" -ceb -d c:\afacts\doctemp -s
which is the equivalent of searching for:
-c "judge AND magnum"
If you wanted to search for the exact phrase "judge magnum" you'd put it in quotes but because you're already using quotes those quotes would need to be escaped, i.e.
-c "\"judge magnum\""
Important: In your question you specified
-cex which indicates Regular Expression. However, you probably want Boolean expression, ie allow use of AND, OR, NOT, NEAR, etc. Therefore I've changed the command line to specify