Why not use the WaitAliasChild in an "if then" statement and have it simply break out on an error? Something like
if Not Aliases.sys.IEXPLORE.pageEcommittingLogin.WaitAliasChild("buttonContinue", 10000).Exists
then Log.Error("didn't work")
else
Call Aliases.sys.IEXPLORE.pageEcommittingLogin.buttonContinue.Click
endIf
Sorry if my syntax is bad... essentially, the above will wait 10 seconds and then return false if it doesn't exist or true if it does. Varying the number varies the length of time you wait... so, effectively, this is the same as putting a counter in your "While" loop to loop X number of times, delaying 1 second each...