More error check in CountPerson method

diff --git a/DKCrutch.lua b/DKCrutch.lua
index 8248738..4809f8a 100755
--- a/DKCrutch.lua
+++ b/DKCrutch.lua
@@ -303,10 +303,10 @@ function DKCrutch:CountPerson(time, event, sguid, sname, sflags, dguid, dname, d
 		local stype = 0;
 		local dtype = 0;

-		if (sguid) then
+		if (sguid) and (sguid:sub(5,5)) and (tonumber(sguid:sub(5,5), 16)) then
 			stype = (tonumber(sguid:sub(5,5), 16)) % 8;
 		end
-		if (dguid) then
+		if (dguid) and (dguid:sub(5,5)) and (tonumber(dguid:sub(5,5), 16)) then
 			dtype = (tonumber(dguid:sub(5,5), 16)) % 8;
 		end
 		if (bit.band(dflags, COMBATLOG_OBJECT_REACTION_HOSTILE) == COMBATLOG_OBJECT_REACTION_HOSTILE) and (bit.band(dflags, COMBATLOG_OBJECT_AFFILIATION_OUTSIDER) == COMBATLOG_OBJECT_AFFILIATION_OUTSIDER) and ((dtype==0) or (dtype==3)) then