For several months, I've been unable to delete folders and PDFs from my Google Docs account (for some folders, I think it has been for over a year now).

I have hundreds of documents (600+) and it's now a complete mess – I use Docs for school and personal purpose. I can delete documents, spreadsheets, and presentations, but every time I try to delete either a PDF or a folder (one by one or in mass, by right-click, delete button or drag'n drop, by night or day and from every existing web browser), I get a "The server encountered an error. Please try again later.". I thought few months was enough to fix this problem...

There are plenty of threads in the official Docs forum:
http://www.google.com/support/forum/p/Google+Docs/thread?tid=767445d2f45ad5e2
http://www.google.com/support/forum/p/Google+Docs/thread?tid=79ec87947005ba75
http://www.google.com/support/forum/p/Google+Docs/thread?tid=0f8818c26bf27063
http://www.google.com/support/forum/p/Google+Docs/thread?tid=24c2fcfb2965de9f
http://www.google.com/support/forum/p/Google+Docs/thread?tid=5f2fde3615f8d163
http://www.google.com/support/forum/p/Google+Docs/thread?tid=1a1ce0a0ab92b396
http://groups.google.com/group/How-to-Documents/browse_thread/thread/9a0428dc0d6a6642/53dc3407884c13a5?hide_quotes=no&pli=1
http://www.google.com/support/forum/p/Google+Docs/thread?tid=4b1206dfbed4b38d

Have any of you face this problem? Have you found a good workaround?

It's not even considered a "know issue": http://docs.google.com/support/bin/static.py?page=known_issues.cs

BTW, they say the storage limit for PDFs is 100. I actually have 382 of them in my account, which may cause the aforementioned problem. Have any of you exceed this cap?

I've had similar trouble
http://pinstack.blogspot.com/2009/04/google-customer-support-issues.html
http://pinstack.blogspot.com/2009/05/better-customer-support-systems.html

tl;dr
Companies like Google and Facebook usually rely on customers to help out other customers and don't offer any real customer support. It's a great system for what it does (address user errors which are 99% of all problems), but what it doesn't do is solve problems that are on google's (or facebook or whatever company) end. The solution: ppublic bug tracking and/or super users.

P.S. it would be really cool to see philipp writeup something about this and bring it to el goog's attention! xD

They're probably overloaded with information. Because users don't bother checking for duplicates and because the system doesn't make post merging possible.

If I could suggest to an author to merge his post in an older one (as Blogoscoped forum admins do manually), and if he accept, we could have much less noise and few conversation but with a lot of information.

Moreover, with contributors categorized in levels, they could give top ones the power to merge report without authors' consent.

I'd really like to see what tools Googlers use to track those feedbacks.