Yes there is a syntax error:

Code:
sigstrength:

    IF jump = 1 THEN rssioff     ; check input to reset to serial                                             
    DEBUGIN  3000,sigstrength,[WAIT("aSSRSSIS-"),dec3 sigfield]    ; get slave signal strength value                                        
    DEBUGIN  3000,sigstrength,[WAIT("aMMRSSIM-"),dec3 sigcontrol]  ; get control signal strength value 
    
    LCDOUT  $FE,$80," Light Unit ",sigfield                                       
    LCDOUT  $FE,$C0," Control Unit ",sigcontrol                                         
    GOTO sigstrength
And I wonder, wasn't that giving you a compilation error before?

Ioannis