Remove that link or fix the functions below. You are using eval which can be easily exploited. I also have a feeling this gives out eval errors with people having spaces in their names. Use stuff like $DeathSchedule::Name[%client.getPlayerName()]
Here is your main problem.
function endDeathTimer(%client)
{
   eval("if (isEventPending($" @ %client.getPlayerName() @ "::DeathSchedule)) { cancel($" @ %client.getPlayerName() @ "::DeathSchedule); }");
   %client.DeathTimer = "";
   %client.bottomPrint("", 0.01); //removes the bottomprint
}
function startDeathTimer(%client)
{
   if (%client.player && %client.player.getDamagePercent() < 1) //if player exists and player is not dead, then
   {
      %client.DeathTimer = 10; //initializing
      %client.bottomPrint("\c5Time to re-enter vehicle: " @ %client.DeathTimer);
      eval("%client = " @ %client @ "; if (isEventPending($" @ %client.getPlayerName() @ "::DeathSchedule)) { cancel($" @ %client.getPlayerName( @ "::DeathSchedule); } $" @ %client.getPlayerName() @ "::DeathSchedule = schedule(1000, %client, decrementDeathTimer, %client);"); //we do cancel here because onUnmount actually runs a LOT of times at once, so this makes the schedule not repeat. thanks Blockland.
   }
}
function decrementDeathTimer(%client)
{
   if (%client.player)
   {
      if (%client.DeathTimer > 0 && %client.player.getDamagePercent() < 1) //if player exists, not already mounted, and player is not dead, then
      {
         %client.DeathTimer--; //decrement timer
         %client.bottomPrint("\c5Time to re-enter vehicle: " @ %client.DeathTimer);
         eval("%client = " @ %client @ "; $" @ %client.getPlayerName() @ "::DeathSchedule = schedule(1000, %client, decrementDeathTimer, %client);");
      }
      else
      {
         if (%client.player.getDamagePercent() < 1 && (%client.DeathTimer !$= ""))
         {
            %client.player.kill();
         }
         endDeathTimer(%client);
      }
   }
   else
   {
      endDeathTimer(%client);
   }
}
Tip on using eval: Avoid it unless you REALLY need to use it - there are many ways of doing what you tried to do in eval without using eval
Eval is extremely dangerous if there is a tiny mistake in it