There's definitely something up with your editor, I would recommend that you try upgrading to the newest version of Joomla - 1.5.23, and that may fix it. Otherwise try the JCE Editor, or if you're comfortable working with straight code, RokPad is always a good option.
The difficult we do immediately, the impossible takes a little longer.
I hear that. I honesty think that maybe it didn't install right or something strange happened with yours. There are way better options, JCE offers the same type of interface with more features. I personally prefer RokPad but I am a code monkey. TinyMCE is good if you are developing websites for clients that need a simple interface, but other than that it lacks features and can cause issues. Just my opinion.
The difficult we do immediately, the impossible takes a little longer.
I much prefer to code thana GUI, but I have been a little lazy as of late using TinyMCE to accomplish the same tasks. This isn't the first time that TinyMCE has bitten me either.
Thank you, Jason Server #1: 4-Cores @ 2.3Ghz | 8GB RAM | Plesk Control Panel v11.0.9 | Apache/2.2.3-65.el5 | mySQL: 5.5.23 | PHP: 5.3.10 Server #2: 8-Cores @ 2.5Ghz | 16GB RAM | Plesk Control Panel v11.0.9 | Apache/2.2.15-15.el6 | mySQL: 5.5.25 | PHP: 5.4.4