When using the clearcase plugin's SCM polling for UCM ClearCase, the commands issued by the plugin cause errors when the stream includes read-only components. This is because the branch type it looks for doesn't exist in other vobs:
( from UCM SCM polling log )
[CMF_CI_int_hudson] $ cleartool lshistory -all -since 1-sep-10.15:36:36utc+0000 -fmt '\"%Nd\" \"%u\" \"%En\" \"%Vn\" \"%e\" \"%o\" \"%[activity]p\" \n%c\n' -branch brtype:CMF_integration -nco foo_vob shared lib
cleartool: Error: Branch type not found: "CMF_integration".
cleartool: Error: Branch type not found: "CMF_integration".

In this case, 'foo_vob' contained the branch type, but not the other two. At best, this is noise in the log; at worst it seems like you might miss changes to the stream's read-only component baseline.