Hello Darac and Raoul, Thank you for your answers. The MIBS and MIBFILES environment variables override the snmp.conf "mibs" and "mibfile". When you add the "+" caracter it should load the list of modules in addition to the default. It works when you export the MIBS=ALL, so the case is that the MIBS snmp.conf entry is just being ignored.
Is this a bug or is it just another undocumented configuration change? The good news is that to set the MIBS=ALL environmentab variable fixed the tkmib issue and now it shows the complete SMI. Thank you Andres