Do i need to check anything >?

I cannot reproduce this issue, sorry. Can you reproduce this with a clean installation?

This is a clean installation. All i have done is created a survey and tried to add the fields.

Try to activate debug mode in /application/config/config.php - see if you get a more specifc error on retry.

I did this and tried but same error :

copied from config-defaults.php
'config'=>array(
// debug: Set this to 1 if you are

looking for errors. If you still get no errors after enabling this
// then please check your

error-logs - either in your hosting provider admin panel or in some /logs directory
// on

your webspace.
// LimeSurvey developers: Set this to 2 to additionally display STRICT PHP error

messages and get full access to standard templates
'debug'=>1,

'debugsql'=>0 // Set this to 1 to enanble sql logging, only active when debug = 1
)
);
/* End

of file config.php /
/ Location: ./application/config/config.php */

THere is no need to copy anything from config-defaults. The setting should alread exist in config.php?

i wasnt sure where it was the file is very jumbled.
i changed only active when debug = 1

The file should not be jumbled. Looks like you have a general server problem somewhere.
Anyway, I cannot reproduce it and so I cannot fix it, sorry. You will need to find out more speicifcson the 500 error - maybe in the server logs?

I did a comfort update and it seems to have resolved the issue!

I am glad it did.