What version of LimeSurvey do you use now?
If you try to import the old survey into LS4, you might try it with LS3.
With what version was the old survey exported? Is there any error message while importing?
In which form do you have these surveys as XML? LSS?
And from which version are these questionnaires? In my experience had not yet problems importing an LSS file created in an older version of Limesurvey into a newer version. What can cause problems currently is import LSS files from LS4 into LS3.
I answer at the LimeSurvey forum in my spare time, I'm not a LimeSurvey GmbH employee.
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