MSIR.0761 ($function) not callable
The indicated $function as invoked as an explicit or implicit Call, but the $function is not callable. An explicit call is one where the $function name is preceded with the Call statement:
call $listAdd('Whatever')
An implicit call is one where the $function invocation is the only thing in a statement:
$listAdd('Whatever')
See the individual function descriptions in M204wiki for details on which $functions are callable and which ones aren't. Note that the only non-Sirius $functions that are callable are $Setg and $Delg. Since $function callability was only introduced in Sirius Mods Version 6.5, not all $functions for which callability might make sense are defined as callable. If there are $functions which you feel would be useful to be callable but aren't currently, make this suggestion to Technical Support.