I had the same problem in Flash Builder. Apparently the Flex compiler doesn't like variables as parameter initializers. Just change the initial values in the parameters from constants to their string value equivalents.
Example:
Throws errors in method parameters: scaleMode:String = ScaleMode.PROPORTIONAL_INSIDE
Doesn't throw errors in method parameters: scaleMode:String = "proportionalInside"
Below is a full example that won't throw errors:
public static function createAround(target:DisplayObject, scaleMode:String = "proportionalInside", hAlign:String="center", vAlign:String="center", crop:Boolean=false, minWidth:Number=0, minHeight:Number=0, maxWidth:Number=999999999, maxHeight:Number=999999999, previewColor:uint=0xFF0000, calculateVisible:Boolean=false):AutoFitArea
