Can you please help with my hector mapping launch file?

I have a LaserScan node "keyencelaser" that is publishing on the topic "scan" with frame "laser_frame" ros::init(argc, argv, "keyencelaser_publisher"); ros::NodeHandle n; ros::Publisher scan_pub = n.advertise("scan", 50); (...) scan.header.frame_id = "laser_frame"; My launch file currently looks like: But I throw this error once I use my launch file: [ INFO] [1482419456.331809455]: lookupTransform base_link to laser_frame timed out. Could not transform laser scan into base_frame. Check failed in file /usr/include/boost/numeric/ublas/matrix_expression.hpp at line 2007: size1 == size2 terminate called after throwing an instance of 'boost::numeric::ublas::bad_argument' what(): bad argument Can someone please help me figure this out? I have tried multiple combinations but can't quite get it.