Error executing transaction handlers' actions

"Error executing transaction handlers' actions" I get this message when I execute the following code below:

private TransactionContext transCtx = null;

protected void BeginTransaction()
{
if (transCtx == null) transCtx = TransactionContextFactory.GetContext(TransactionAffinity.Required);

transCtx.Enter(); // the error happens here!!!
}

This problem doesn't in all PCs. Any idea?
Thanks