no solution, been out of country for 2 days, just confirming I have this also, from the first revision with squirrel and still in today's revision. Suse Linux 10.1 (64bit) GCC 4.1.0
Just did a quick reading of the responses can we add both definitions for the pointer based and reference based (or even pointer reference based) 
I hope this is fixed soon, otherwise I can't debug :-(  (since GDB on winXP64-bit crashes  and now I can't build on linux ...)
Updated to GCC 4.1.2 prerelease SuSe, no changes.... I guess it's a problem of 4.1 series. It seems that when templates are instantiated the definition of Push(SQVM *, wxArrayString *) is not yet known, even it should.....
Inserting this
                ......................
                var(&ProjectFile::weight, "weight").
                var(&ProjectFile::compilerVar, "compilerVar");
SQVM *sss ;                                   <==
wxArrayString *xxx ;                       <==
SqPlus::Push(sss, xxx) ;                 <==
        SqPlus::SQClassDef<CompileOptionsBase>("CompileOptionsBase").
                func(&CompileOptionsBase::SetLinkerOptions, "SetLinkerOptions").
                func(&CompileOptionsBase::SetLinkLibs, "SetLinkLibs").
                ......................
gives no error in inserted lines, so the problem is not a definition missing of Push(SQVM*, wxArrayString *); I think is a template problem in 4.1 compiler. No solution yet   :cry:
<edit>
I found a similar problem in squirrel forum.... I'll ask there if somebody solved it.