Pan mentioned in personal/verification section is invalid ??

You might not have written PAN number in the Last page of ITR-5 where the partener is required to give verification by signing ITR.

Try it with the PAN of firm

first you update profile details with PAN at income tax efiling site and after upload it.

just update your profile by mentioning you pan and date of birth once again as you know Income Tax site has gone through some changes.

CA Sanjiva Kumar Sharma