This not a problem of the installer, quite the opposite, instead. The installer is informing you that your DLL.XML was ALREADY corrupted before running the installer, so it's not going further ahead, and it hasn't even touched it.
You need to fix your DLL.XML that, as I've said, already had a syntax error inside, at line 7.
If you don't know how to fix it, either post it here, or just delete it. In case no DLL.XML file is found, the installer will create a correct one from scratch.