I have tried and failed to replicate this on evo 2.4.1.
Heres is what I did
1) I went to Edit->Preferences my timezone from "Asia/Calcutta" to 
  "America/Denver" and observed that all appointments got shifted by 
   around 12 hrs (as expected)
2) Then i shutdown evolution and clicked on a date in clock applet.
   i got evo calendar opened due to this ..with my "America/Denver" 
   timezone effect still intact.
   Nothing happened... no crash.
Then I tried the same without shutting down evo .. i got 2 calendar views
which are exactly same with "America/Denver" timezone appointments intact.

Is there something I'm missing .. ?

I have tried to reproduce it on my system.

Unfortunately, I suceeded. 

I changed my Evolution timezone to Europe/Prague. I saw all the events
rescheduled. Afterwards, I clicked to change my timezone to Asia/Macau, and the
crash happened again.

There may be a particular problem with the definition of the Asia/Macau
timezone, and evolution crashes when it is changed to this zone.

Please note that I had found no way to recover my Evolution database from the
crash, and I had to delete everything I had there (not really a lot), and start
a clean database.

If you need it for debugging, I can send you my evolution database, there's
nothing really confidential or personal there.

Please note that the version I use is evolution-2.2.3-2.fc4
- the latest update released for FC4.

BTW, I found how to recover from the error.

After reproducing the error, I was again in the situation when Evolution crashed
immediately after started, and I could not access my data, and neither could I
change the timezone to something else then Asia/Macau.

I solved the problem by running

evolution -c=Mail

- asking Evolution to start with component mail. Which is not a valid component
name, but it at least prevented Evolution from opening the calendar. I could go
to Preferences=> Calendar=> Timezone.

I changed the timezone from Asia/Macau to Asia/Hong_Kong - which is at all times
the same, and Evolution works for me again.

Apparently, the Asia/Macau timezone definition is corrupted.

My system is a regularly updated Fedora Core 4 (with all updates released in
FC4-updates as far as 2005-10-19).

The versions of relevant packages on my system are:

tzdata-2005m-1.fc4
evolution-data-server-1.2.3-3.fc4
evolution-data-server-devel-1.2.3-3.fc4
evolution-devel-2.2.3-2.fc4
evolution-2.2.3-2.fc4

I have checked that these packages are not corrupt; 
rpm --verify tzdata-2005m-1.fc4 evolution-data-server-1.2.3-3.fc4
evolution-data-server-devel-1.2.3-3.fc4 evolution-devel-2.2.3-2.fc4
evolution-2.2.3-2.fc4

does not print any error.

I have reproduced the error: changing timezone from Asia/Hong_Kong to Asia/Macau
causes Evolution to crash upon opening calendar; changing it back solves the
problem.

thanx. I too get the crash with "Asia/Macau"
Will look into it as soon as possible.
Assigning it to myself.

*** Bug 318101 has been marked as a duplicate of this bug. ***

This bug and the likes (e.g. 318101) are due to a spelling mistake
timezone information

Please follow the steps given below to get rid of this bug
1) Locate for Macao.ics (yes ... not Macau) file in your installation area.
2) Once u find it, rename it to Macau.ics 
3) open this renamed file, change all instances of Macao to Macau.
4) Locate for a zones.tab file and change the spelling if necessary .. there too.

restart evolution.

Thank you, the solution works for me.

:-) please not that I would not call it a spelling mistake but rather a spelling
inconsistency - both Macao and Macau and correct spellings, the first one in
English and the second one in Portuguese.

Quoting from http://en.wikipedia.org/wiki/Macau#Names

<quote>
The form "Macao" was the original Portuguese spelling, and has been retained in
most European languages. In modern Portuguese, the correct spelling is "Macau".
During the 20th century, the official spelling "Macau" became more and more
common in English-language sources, including most print media.

Since the handover of sovereignty, the government of Macau considers "Macao" the
official English spelling of the name, whereas "Macau" remains the official
spelling in Portuguese. This is the practice followed in official documents such
as passports and immigration forms.
</quote>


Of course, the bottom line is that from the programming point of view, the
spelling must be consistent. I do not know what the policy is: whether the
zonename should be the English spelling or the spelling in the local language.

As a suggestion to prevent similar problems in the future: Shouldn't Evolution
do some sanity checks to avoid a crash in case the timezone definition is not found?

I agree, it is generally the case that sanity checks are done.
We just happened to overlook this one.
the code here will be cleaned now to avoid crashes.. thank you.

in evo 2.5.2

Is this still a valid issue?

Could you please check if this has been fixed with the latest stable release (2.22.x)?

I believe it's not an issue anymore.  Just from looking at my Evolution installation, it does not look like Evolution installs individual timezone ICS files anymore.  I don't know if it now relies on systemwide timezone database - but I think the issue is now long gone.  I think it's safe to close the issue now.

Cheers,
Vladimir

Yes.. Evolution uses system timezone information since the 2.12 series.