There are two main things that can cause erase to misbehave:

• It actually calls a macro, so if your macro file is corrupt the command may not load properly. There was a bug in an earlier version that could cause corruption of your in-memory version of the macros, hence the importance of the update. The update should also have replaced your macro file on disk. You can check that your macro file looks sane by going to tools -> macros -> edit macros, scroll down in the dialog, and check that the last line is ENDM (followed by a blank line)
• Your selection method may be changed. This should make all commands requiring a selection to misbehave though, and not just erase, but you can reset it to the default by going to tools menu -> options -> Select method -> set to dialog or popup.

If none of this helps, I suggest you contact support through your registered user pages.

Today I am adding Pappy's Pub by @Shessar:

Great work. Added it to the tutorial list.

This time it is @arsenico13's entry going into the atlas:

Lines can unfortunately just have a single path, they can't branch, so an additional section like that cannot be part of the line. What I would probably to in this case is to draw the outer line as a single line, and then have that "inner" vertical line as a separate line, and make sure to arrange the lines so it is below, not above the outer lines. This will give you much better corners.

Otherwise, it would have to be made as a polygon, which is doable, but a bit more work.