If QuickTime is installed by default under Mac, this is not the case on Windows machines.
If you want to check if QuickTime has been installed on your machine, you might try the following code.

PICTURE TYPE LIST($array1;$array2)

If the size of any of these arrays is greater than one, it's most likely that QuickTime is installed.

GET PICTURE RESOURCE(9000;$vPicture) ` To load a picture
If (ok=1)
PICTURE TO BLOB($vPicture;$myBlob;"JPEG") 
End if

Also, the code above will try to convert a picture into JPEG format. If the blob size is 0, the picture has not been converted and QuickTime is not installed.