Hi,
Apparently Anno 1404 has protections in place to prevent save editing. Yes, you will disable achievements by attempting to load a modified save.
You probably made a small mistake during your editing process. Start over from backup and be even more careful.
However you say you used the correct tools — RDA Explorer and Notepad++ — which means you know what you're doing and the hacking process might work.
As long as you correctly preserved the original file format and inner folder structure during your edit:
• game xml file must stay in root, modify / overwrite the one already there
• that means no duplicates; delete the old, import the new, keeping the old name. So no " - copy (2)" at the end
• no erroneous changes in any imported files, namely:
• respect the XML file syntax, do not mix data types, put parameter strings in quotes, but not values (unless w/ CDATA)
• close all opened tags properly, use a validator service if unsure (w3schools has a good xml_validator page)
• no extra files imported by accident
• no dangling folders, and most importantly; no parent folders around the imported file
• always use "save as", to keep backups around
• do not convert the file format - If notepad offers to change encoding, endianness, unify EOL format, put EOF, delete (or add) UTF8-BOM, say No!
• Is there a checksum / anti-tampering measure? Defeating it will be hard, so hopefully nothing of the sort.
If after all that, Anno still yields error; show your work; Attach some text excerpts from the changed file (copy full lines of before/after the edit into your reply), and even pictures of everything you touched. Especially the folder structure inside the *.ssw file container.
Good luck!
--3ICE
