I have installed Limesurvey 192+ build 120919 on my 1and1 webspace and imported a survey that was running on the same revision of Limesurvey but on a webfusion webspace. The survey seems to work correctly until I get to the stage of exporting the results to an Excel file.
The file is downloaded. but when I try to open the file, Excel tells me the file contents do not match the file extension, and when I open the file it is just unintelligible gibberish.
Can anyone please help

I'm sorry, that LimeSurvey version is far too old for us to debug. Please upgrade your version to 2.06 stable (at least) and retest.

I understand your answer, however the 1and1 hosting platform I have does not support PDO on MySQL, so as far as I am aware I am unable to upgrade to any of the Version 2 installs of Limesurvey. I just wondered if anyone else out there has had a similar experience on 1and1. I do haver a work around in that exporting to CSV files works OK. I just have to remember to monitor for any extra long text submissions. I also note that exporting to a .doc file works OK.

You should really think about upgrading. If your hoster can't support the requirements of Limesurvey (which are not very demanding) you should even think about getting a new host.

Your version is pretty old (almost 4 years now, which is an eternity in web applications) and it is not supported with bug fixes or security fixes.