OpenMp Fatal user error 1002

Question

Hi, I'm using a basic omp parallel for, which works most of the time, but sometimes (with no difference in the input data) makes the program crash with the error:

Fatal user error 1002

Not all work sharing construct executed by all threads.

#pragma omp parallel for \
        shared(szDetailedError, aCG) \
        private(pChannelGraph, szError) \   
        num_threads(8)
for (int i=0; i<aCG.size(); ++i)
{
    pChannelGraph = aCG[i];
    szError = pChannelGraph->getCurve()->applyFilter(szFilter);
    if  (   !pChannelGraph->getCurve()->isSgrm()
        &&  szError.isEmpty()
        )
    {
        pChannelGraph->updateLegend(m_aFilterNames.join("\n"));
    }

    if (!szError.isEmpty())
    {
        szDetailedError += QString("%1\n\n").arg(szError);
    }
}

What's causing this error, and how can I fix it?

Thanks.