Sending Images via iMessage with AppleScript

Using AppleScript to send a message via iMessage, I can send plain text just fine. However, when I try to send a file, Applescript wants to send it using colon delimited paths and Messages doesn't understand how to interpret that.

#Capture an image of the main room camera

set {year:y, month:mo, day:d, hours:h, minutes:mi, seconds:s} to (current date)

set theFile to "/Users/ladmin/Documents/MotionAlarm/AlarmImages/" & y & "-" & mo & "-" & d & "-" & h & "-" & mi & "-" & s & ".jpg"

set theAttachment to POSIX path of theFile

tell application "SecuritySpy" to capture imageastheFilecamera number 1

delay 5

#Send that image via iMessage

using terms from application "Messages"

tell application "Messages"

set myid to get id of second service

set theBuddy to buddy "buddy@me.com" of service id myid

send "Motion detected!" to theBuddy

sendfiletheAttachmenttotheBuddy

end tell

end using terms from

You get the following error in Console:

4/30/13 10:44:52.262 PM imagent[539]: [Warning] Linking failed with error Error Domain=NSCocoaErrorDomain Code=260 "The file “/Users/ladmin/Documents/MotionAlarm/AlarmImages/2013-April-30-22-44-46.jpg” couldn’t be opened because there is no such file." UserInfo=0x7ff9cac51050 {NSFilePath=/:Users:ladmin:Documents:MotionAlarm:AlarmImages:2013-April-30-22-4 4-46.jpg, NSUnderlyingError=0x7ff9cac34760 "The operation couldn’t be completed. No such file or directory"}

Any suggestions?