Got some new errors

I installed the Webform 2 PDF anf first it was working quite good.
Then I made some changes and now I have only errors ..

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Notice: Trying to get property of non-object in webform2pdf_download_pdf_form() (Zeile 85 von /home/www/web388/html/pm/sites/all/modules/webform2pdf/includes/webform2pdf.download.inc).
Notice: Trying to get property of non-object in webform2pdf_download_pdf_form() (Zeile 86 von /home/www/web388/html/pm/sites/all/modules/webform2pdf/includes/webform2pdf.download.inc).
Warning: date_timezone_set() expects parameter 1 to be DateTime, boolean given in format_date() (Zeile 1938 von /home/www/web388/html/pm/includes/common.inc).
Warning: date_format() expects parameter 1 to be DateTime, boolean given in format_date() (Zeile 1948 von /home/www/web388/html/pm/includes/common.inc).
Notice: Trying to get property of non-object in webform2pdf_download_pdf_form() (Zeile 90 von /home/www/web388/html/pm/sites/all/modules/webform2pdf/includes/webform2pdf.download.inc).
Notice: Undefined index: in _webform_filter_values() (Zeile 2942 von /home/www/web388/html/pm/sites/all/modules/webform/webform.module).
Notice: Undefined index: in webform_component_include() (Zeile 3516 von /home/www/web388/html/pm/sites/all/modules/webform/webform.module).
Notice: Trying to get property of non-object in webform2pdf_download_pdf_form() (Zeile 85 von /home/www/web388/html/pm/sites/all/modules/webform2pdf/includes/webform2pdf.download.inc).
Notice: Trying to get property of non-object in webform2pdf_download_pdf_form() (Zeile 86 von /home/www/web388/html/pm/sites/all/modules/webform2pdf/includes/webform2pdf.download.inc).
Warning: date_timezone_set() expects parameter 1 to be DateTime, boolean given in format_date() (Zeile 1938 von /home/www/web388/html/pm/includes/common.inc).
Warning: date_format() expects parameter 1 to be DateTime, boolean given in format_date() (Zeile 1948 von /home/www/web388/html/pm/includes/common.inc).
Notice: Trying to get property of non-object in webform2pdf_download_pdf_form() (Zeile 90 von /home/www/web388/html/pm/sites/all/modules/webform2pdf/includes/webform2pdf.download.inc).
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Whats going wrong? I did not change somthiong at the module or at the rigths

Would be nice if I (nwebee) could get information concerning this ..