find this line
Code:
if( newevent == "UNIT_SPELLCAST_START" ) then
local spellName, spellRank, displayName, texture, startTime, endTime, isTradeSkill, castID, notInterruptible = UnitCastingInfo(unit)
remove spellRank. it is the second parameter in this case (or nameSubtext)
also add 'local spellRank = "" ' after in case the addon was using it somehow
and same thing with two occurrences for UnitChannelInfo in CHANNEL_START and CHANNEL_UPDATE event handlers
but regarding the first two errors you mentioned i don't know and i don't have the beta