I'd say timer33 is executing a command which is expecting an octal number (eg. 037777777777) and instead it's getting an integer (08). Might be a scan command or a binary command.
no, more likely its a command expecting the decimal integer 8, but something has prepended it with a 0, thus making tcl try and interprate it as octal (all numbers starting with 0 are treated as octal in tcl). and since 8 is an invalid octal value, it errors
proc oct_to_dec {number} {
while {[string index $number 0] == "0"} {
set number [string range $number 1 end]
}
if {$number == ""} { set number 0 }
return $number
}