Sometimes people complain about a Tab Mix Plus development version (or a release) being incompatible. You are welcome to try other, older builds but keep in mind that Tab Mix Plus is always compatible and always working, even with Beta, Aurora and Nightly, despite Firefox incompatibility warning you might be seeing.
Although older version may work for you without a problem it is very important that you report about any problem.
The problem you encounter can be incompatibility with other extensions or a bug in Tab Mix Plus that only reveals itself in a specific Firefox and Extensions combination. Installing old version will not fix the problem.
If you haven't read How to post about a problem, read it now.
If you are testing pre-release Firefox versions, you really should install Disable Add-ons Compatibility Check, Add-on Compatibility Reporter, or simply search AMO for something similar, there's a whole bunch available now. While it may not eliminate the warning, it will allow you to install and use add-ons with pre-release Firefox versions.
Remember to always use the latest development version available with latest Firefox pre-release versions, let it be Beta, Aurora or Nightly.