I could create a subfolder but if i try to delete it

[nickhere]

it causes a exception
from 2=@100pureessentialoils.com
//account.incomingServer.rootFolder.createSubfolder(from2, msgWindow);
account.incomingServer.rootFolder.deleteSubFolders(from2, msgWindow);
/*
Exception: [Exception... "Could not convert JavaScript argument arg 0 [nsIMsgFolder.deleteSubFolders]" nsresult: "0x80570009 (NS_ERROR_XPC_BAD_CONVERT_JS)" location: "JS frame :: Scratchpad/1 :: <TOP_LEVEL> :: line 20" data: no]
*/