diff --git a/xCAT-server/lib/xcat/plugins/aixinstall.pm b/xCAT-server/lib/xcat/plugins/aixinstall.pm
index 77afb7218..a2da8b590 100644
--- a/xCAT-server/lib/xcat/plugins/aixinstall.pm
+++ b/xCAT-server/lib/xcat/plugins/aixinstall.pm
@@ -154,6 +154,13 @@ sub preprocess_request
     #	- either the NIMprime attr of the site table or the management node
     my $nimprime = xCAT::InstUtils->getnimprime();
     chomp $nimprime;
+    if (!defined($nimprime))
+    {
+       my $rsp={};
+       $rsp->{error}->[0] = "Could not determine nimprime. Check if nimprime defined in site table or site table master is not resolvable to the MN name.";
+       xCAT::MsgUtils->message("E", $rsp, $cb,1);
+       return undef;
+    }
     my $nimprimeip = xCAT::NetworkUtils->getipaddr($nimprime);
     if ($nimprimeip =~ /:/) #IPv6
     {
@@ -4233,7 +4240,7 @@ sub mk_spot
             if ($::RUNCMD_RC != 0)
             {
                 my $rsp;
-			    push @{$rsp->{data}}, " The cpcosi command failed. \n$output\n";
+				push @{$rsp->{data}}, " The cpcosi command failed. \n$output\n";
                 push @{$rsp->{data}},
                   "Could not create a NIM definition for \'$spot_name\'.\n";
                 xCAT::MsgUtils->message("E", $rsp, $callback);