Instructions:
SRC and DOC folders are not modwise important. Data, scripts and sfx are. Highlight them and then copy them. Then go to your Bridge COmmander Root folder (e.g. the folder that has other folders called, data, scripts, sfx, Screen Shots, Saves and that stuff) and paste.
To put it simply, you don't really need the SRC folder.
Edit: The SRC folder is a backup of the KM scripts folder. In case you get the black screen of death e.g. a BSOD.