The Help Page writers and the error message writers don't seem to communicate with each other or read each other's work. The term "restriction" means something different to each. The "restriction" you are facing simply means that you ran into a limit and can't commit to buy something (unless you can and do immediately pay for it) until you are again below your limit.
That error message seems to be associated with running into your Open Transaction Limits. To get below your limits you need to pay for the outstanding unpaid items that now count towards your limits, but that might not be immediately possible because eBay counts items that you committed to buy but cannot pay for at this time against your limits:
1. At least some active auctions that you have bid on (including the one you are trying to rebid on). Originally only those you were in the lead on counted, but it is very likely that the rules have changed since they were last made public to include your outbid bids on running auctions and also any pending Best Offer. To minimize the effect of these wait until near the end of the auction to bid only one time at your TRUE maximum you are willing to pay for the item, and then pay immediately after it ends, to minimize the time it counts towards your limit. You can't pay until you win, so don't use up your open transactions on bids you can't pay for until hours or days later.
2. Transactions cancelled at your request (or due to problems with your address). Note that these also can result in lowering the limit, so make sure you are going to buy (and CAN buy, that the item ships to your location) BEFORE you commit to buying.
3. Unpaid Item Strikes. Again, don't bid/commit to buy unless you KNOW you can and will pay for every item.
To get these and other buying limits raised or removed in the long run you need to establish a pattern of reliably paying for what you commit to buy.
