Error: Unable to resolve nonexistent file

It looks like the CSV file has the dates in mm/dd/yyyy format rather than dd/mm/yyyy. Hence the invalid date exception with the 31st month.

This will work:

date parsedDate = date.parse('31/5/2013');

This will fail with "System.TypeException: Invalid date: 5/31/2013"

date parsedDate = date.parse('5/31/2013');

From the Date.parse methods docs:

Constructs a Date from a String. The format of the String depends on the local date format. The following example works in some locales:
date mydate = date.parse('12/27/2009');

You can find the locale Date format information in the Supported Locales docs.

Another option would be to use the date format YYYY-mm-dd and date.valueOf().

Assuming you have already set up Visual Studio Code and installed the necessary extensions:

It is as easy as right click the folder in VS Code to delete > SFDX: Delete From Project and Org

Note: If you accidentally renamed your LWC in VS Code and pushed it into your org (e.g. Renamed "LWC_Eample" to "LWC_Example"), the old LWC "LWC_Eample" will still be visible in your SFDC org but not present in your VS Code.

If this happens, go to your VS code project, Right Click your "Manifest > Package.xml" > Retrieve Source in Manifest from Org.

Presto, your old LWC "LWC_Eample" will appear in VS code. Then you can proceed to SFDX: Delete From Project and Org