The code is not publiclly available, it was written for us and donated to us by the late JohnH.
However with that said here is the parts of the code that was giving them trouble... (Imagine going through all of this, and this is just a fraction of the code JohnH wrote for us!)
5 SCS=30:NVERSF=0:TSID17T=0:STARTSDT=0
IM NID16(SCS),VN16(SCS),SN16(SCS),LSN16(SCS),J16(SCS) ,T16(SCS),SF16(SCS),F16(SCS),K16(SCS),TID16(SCS),Z 16(SCS),PC16(SCS)
10 GOSUB 30000
20 J=0:F16=9:R16=0:M16=0:SL16=0:XC=0:X=1
C16=200:NID 16(1)=30000:SN16(1)=30000
=1:H16=0:H0=0:H32=0:H33=0:H17=0:Q17=0
100 J=J+1:GET 1,J
101 IF A$="G" THEN 102 ELSE 100
102 GET 1,J+188:IF A$="G" THEN 108 ELSE 100
108 IF J<50000! THEN 100
110 GET 1,J+1:K=ASC(A$):IF K>127 THEN K=K-128:E=1
RINT "TRANSPORT ERROR":GOTO 111 ELSE E=0
111 IF K>63 THEN K=K-64:S=1:GOTO 112 ELSE S=0
112 IF K>31 THEN K=K-32
=1:GOTO 120 ELSE P=0
120 GET 1,J+2
ID=K*256+ASC(A$)
130 GET 1,J+3:K=ASC(A$):IF K>127 THEN K=K-128:SCR=2:GOTO 131 ELSE SCR=0
131 IF K>63 THEN K=K-64:SCR=SCR+1
132 IF K>31 THEN K=K-32:AFC=2:GOTO 133 ELSE AFC=0
133 IF K>15 THEN K=K-16:AFC=AFC+1
134 C=K
135 IF AFC=0 THEN J=J+188:GOTO 102
140 IF S=0 THEN T=J+4:SF=0:GOTO 141 ELSE GET 1,J+4:T=J+5:SF=J+5+ASC(A$)
141 GET 1,T:IF PID=16 THEN 176
145 GET 1,T:IF PID=17 THEN 180 ELSE J=J+188:GOTO 102
150 IF T>=J+187 THEN J=J+188:GOTO 102 ELSE T=T+1:GOTO 141
160 J=J+188:GOTO 102
176 IF H16=4 THEN J=J+188:GOTO 102 ELSE IF R16=1 THEN K16=ASC(A$):GOTO 1000 ELSE IF S=0 THEN 150 ELSE SL16=0:T=SF:R16=1:GET 1,SF:K16=ASC(A$):Z16=1:GOTO 1000
180 IF R17=1 THEN K17=ASC(A$):GOTO 5000 ELSE IF S=0 THEN 150 ELSE SL17=0:T=SF:R17=1:GET 1,SF:K17=ASC(A$):Z17=1:GOTO 5000
1000 IF Z16=0 THEN Z16=1:GOTO 150 ELSE Z16=0:IF SL16=0 THEN SL16=5005:F16=9:GOTO 1050 ELSE SL16=SL16-1:F16=F16+1:GOTO 1050
<snip>