IT looks to me that you got a carriage return after the comma, thats why you got trouble. I can see two approaches:
1 - Edit the list by hand, deleting the last character after the ","; or
2 - Replace the carriage returns by "", like this
[lista]= "1234,
2345,
345 ,
1234"
REplace(Replace([lista];Char(10);"");Char(13);"")
cheers,
ROgerio