If you can live without Tortoise SVN, or at least live without it long enough to try removing it, rebooting, and trying out SlickEdit again, that may be worth a shot. For reference, I've got Tortoise SVN 1.4.5, build 10425 on both my home and work machines.
I find using the file manager is easiest when you have configured your most-often used directories as directory aliases in SlickEdit. To do this, go to the Tools > Options > Aliases menu command. In the resulting dialog, double-click aliases.slk, which should be the top entry. In the next dialog to pop up, make sure the "Surround with" checkbox in un-checked. Click New. Think of a short, easy-to-remember name for a directory you're browsing to all the time, and put it in the text field. For example, if you had a directory called C:\FileSync\FromFTP, a good alias might be fsftp. Click OK. Make sure your new alias is highlighted and then type the full directory path in the right-side field. (Screenshot: aliases.gif attached)
Once you've got some directory aliases set up, you can then use the cd command on the SlickEdit commandline. For this example, you'd type cd fsftp, and then press Ctrl+Space, which will expand the alias. Press enter, and your current working directory will be set.
From here, you've got two ways to quickly edit your files. The first is to use the edit command on the SE commandline. Activate the commandline and type edit filename.ext (you'll get autocompletion help as you type), and press enter once you've entered the file you want.
The second way is to use the file manager. Activate the commandline and type fileman, and press enter. A dialog will appear asking for a file filter. If you leave it blank, you'll get *.* by default. Once you click OK, you'll get a text-mode directory listing in what looks like a plain text file. Use the arrow keys to move up and down the listing. Once you've found the file you want, you can double-click the line, or use the arrow keys to make that line the current one and press enter.
