As Joe also said, don't rename your user profile. Windows will not like that at all. Instead, it is better to make a new profile using that name and just switch to that. But the desktop is really no good place keeping these files, so doing that is more a band-aid than anything really. As Joe suggested, it is better to fix the problem.

The command Joe mentions is documented in the Blog article, under the heading "Four B – Fixing the Map", under the subheading "Everything at Once" (But I recommend reading the whole thing, don't just that section)

As for symbol catalogs, you don't normally import those into your drawing. You open the symbol catalog in the symbol catalog window using the :ICON_CATALOG: button, and simply use the symbols from there. Symbols will then be imported into the map one by one as you use them from the symbol catalog (But do note that symbols are indexed by their name, so if you have a symbol with a certain name already in your map, it will use that, even if the one in the catalog is different but with the same name)

Are you 100% sure of that? I grabbed a random symbol that gave me a red X and the path of it was C:\Users\Jer\Desktop\Mirage\The World of Mahdran\Massive World of Mahdran\4x4 Massive World\Grey Spectrum Mountains\Stones\Lavastone.png

Now, this immediately rises some red flags, because even if you did put the symbols on the desktop of the new computer, the path would only be the same if your username ("Jer" in this case), is the same on your new computer. If it isn't, then putting them on the desktop on the new computer will not result in the same path, the only thing you can do in that case is to manually recreate that exact path (Windows doesn't mind you creating additional folders under "Users" even if it isn't a user, but you need admin privs to do so.)

(You can check the actual path by right clicking on any of your images and select properties, the properties dialog will contain the full path of the current location)

Generally, keeping files on your desktop is NOT a good idea, precisely because of issues like this. I always recommend keeping all resource files inside the CC3+ data directroy, because that way, you can use relative references in your paths, meaning it will work even if the data directory isn't in the same location on the new computer.

There's a lot of information in this blog entry about dealing with this:

It's just an illusion caused by the shape of the poly, the size of the red X, and the fact that it is in the background partially covered by other fills. Look closer at it, and you'll see the sharp straight edges between the red X and the white background.

The crosshair isn't actually a color. It is drawn as the negative color (XOR) for anything it is over, so when over a dark background, it is light, and over a light background it is dark.

The problem lies here:

A 2D polygon isn't a path, it is a polygon. When applying the river draw tool, which is a line-type tool to a polygon, you get weird effects. When a line has a line width, it is shown as a solid entity of that width, but when a polygon gets a line width, it is shown as a hollow entity with an outline of that width.

So why was in converted to a Polygon instead of a Path? This is down to the fact that the river isn't made up from just one series of lines, but they are actually doubled up. This causes CC3+ to see interpret this as a set of lines that goes all the way to the end and back to start again, so since it ends where it started it is interpreted as being a polygon. This means you get a very thin polygon, but a polygon still.

You can easily get this into the desired path by using the :CC2BREAK: command on it. Just place the start of the break at one end of the new "polygon" and the end of the break at the other end. This will basically remove one half of the poly, and leaving behind the line representing the other half as a proper 2D Path.