Things like that can be expected in a beta.

Content Encoding Error - If you get the error message, Content Encoding Error or The page you are trying to view cannot be shown because it uses an invalid or unsupported form of compression, use these steps to diagnose and fix them:
Check the settings of any Internet security applications you use (including firewalls, anti-virus or anti-spyware programs, and privacy protection programs). You should try to remove any permissions those applications have for Firefox, and then add them again. For program-specific instructions for a number of applications, see Firewalls.

Follow the Standard troubleshooting steps.

Source

Usual suggestions are to clear cache or cookies

How to clear the cache | How to | Firefox Help

Clearing private data | How to | Firefox Help

But yes, it is a Beta (gotta love Opera, never have to help anyone fix it )

A Guy

Heyyou said:

Things like that can be expected in a beta.

I certainly agree with that - BUT -

In a previous debate about FF, I mentioned the fact that the last few (non-Beta) upgrades in FF have seen this message appears when I try to access my ISP webmail address -

"Firefox no longer supports this technology."

I have to use Hotmail in IE9 to use my Webmail address and/or contact my ISP. Many add ons and features, which once worked perfectly in FF, are no longer supported, but still work well in IE. Some newer add ons and features seem to have no specific purpose. Useful stuff, e.g. PDF Download, Download Helper and X-Marks, is great, but there are now so many add ons which seem to have no benefit, at least for me.

I am going to give the next FULL FF upgrade a chance. If things remain as they are, I will migrate to IE9. I am aware that there are others, such as Opera, but I have tried those and found them wanting.

My feeling is that IE has been slowly improving, whilst FF has become bloated and is missing the original purpose, intended by its first dev's. IE has learned from FF that you have to give the people what they want. I also feel that Microsoft learned a similar lesson with XP, forgot it and produced Vista, then remembered it and gave us Windows 7, which I personally feel is the O/S which is as suited to its time and place, as was Win98 SE, which I remember fondly. And I still possess a full copy, with all relevant books and discs.

Firefox just need a faster launch like Chrome. Then it will be the best!

I'm using Chrome!

I use Google Chrome ......