Converting some old code, SC7 complained about strings.txt for two plugins. The problem seemed to be that the plugins were originally written on Windows, so when I copied Plugin.pm and pared it down to make strings.txt, my strings.txt files had DOS line endings. Slim/Utils/Strings.pm uses chomp() to remove line endings (I'm not a fan of chomp) which leaves DOS \r at the end of strings when SC7 runs on Unix. I'd suggest something like the following (untested; I just used dos2unix to fix my files) -- with strings moving out of .pm files and developers on multiple platforms, SC7 shouldn't be so picky.

--- Slim/Utils/Strings.pm       (revision 13905)
+++ Slim/Utils/Strings.pm       (working copy)
@@ -270,7 +270,7 @@
        LINE: for my $line (split('\n', $$text)) {

                $ln++;
-               chomp($line);
+               $line =~ s/[\r\n]//g;

                next if $line =~ /^#/;
                next if $line !~ /\S/;