Can't open a JPEG in Adobe Camera RAW 4.3.1

i'm trying open jpg file bridge acr using cmnd+r combination , nothing happens.

i can view jpg files in acr when apply changes them in lightroom. double click on them (or cmnd+o) , open in adobe camera raw.

anyone can help?

i'm using os x 10.5.2

in bridge > preferences > thumbnails i've enabled checkbox says:
"prefer adobe camera raw jpeg , tiff files"

in photoshop > preferences > file handling > file compatibility i've enabled checkbox says:

"prefer adobe camera raw jpeg files"

in acr > camera raw preferences > jpeg , tiff handling have enabled checkboxes says:

"always open jpeg files settings using camera raw"
"always open tiff files settings using camera raw"

what i'm doing wrong?

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