Try using this..
datablock fxDTSBrickData (brick1x5Data){
brickFile = "./bricks/1x5.blb";
category = "Bricks";
subCategory = "1x";
uiName = "1x5";
iconName = "add-ons/brickIcons/1x14F";
};
Change for brick name; Should be same name.
General Category (on the tabs of the Brick Menu
Sub-Category; Says above category of bricks.
Just make it one that exists; Picture won't show until Badspot fixes the bug
Make sure you save as .BLB, and make sure that when you start a server, you open the add-ons GUI [it's in the "Start a Game menu"].