When I tried to send normally, the amount to send said 3.58215 mBTC, with a fee of 1.56 mBTC.
I tried to create a transaction of 3.59215 mBTC using: Create transaction > From CSV text, but the Transaction box looked all wrong, with 0 BTC sent, and a negative fee!
It took 20 minutes to sign, with the Python process using 900MB of memory. I saved the file, but haven't tried to broadcast it.
I'm not at all familiar with this non-standard usage. Where would I find the raw transaction?

I tried using the method described in the other thread.
I changed MIN_RELAY_TX_FEE =  in /lib/bitcoin.py from 10000 to 1000, and reduced the default fee in the settings from 0.2 mBTC to  0.01 mBTC.
When I tried to send the transaction, the fee was 1.56 mBTC.
After 15 minutes of waiting for it to send, I received an error message:  error: {u'message': u'TX rejected', u'code': -22}

Your described method would have worked fine, except that the amount that I was trying to transfer was 26.04785 mBTC, and the fee was 31.2 mBTC!

I think that my imported addresses contained quite a bit of useless unspendable bitdust.

I have stopped using the Bitcoin Core wallet, and I have imported 2 of the private keys into Electrum, which works fine, except that these addresses aren't included in the wallet seed.
Can I do an internal transfer to move my funds from the imported addresses to native addresses in the Electrum wallet that are supported by the seed?

Recently on Bitmessage there was mention of an altcoin called Spillcoin™.
It seemed to have its own Bitmessage channel: deleted
and there was a website: deleted

UPDATE: Forget about Spillcoin™. The website quickly disappeared, and it turned out that the whole event was just a big wind-up by Bitmessage trolls.

You can run BOINC on it.

OK, thanks for the information.
I figured out what I was doing wrong. I was trying to use Electrum's built-in console.
When I used the menu Wallet>Private keys>import then it accepted the keys in L**** format correctly.

[SOLVED]

I have dumped 2 private keys from my Bitcoin-QT wallet, and they are in L**** format.
How can I get these keys in 5**** format, so that I can import them into an Electrum wallet?

I can't really transfer the funds, as they are mostly bitdust, plus I want to keep the same addresses in Electrum.

I've successfully copied the entire blockchain from one computer to another, so maybe you can do this?

I've got 310 mBTC of useable Bitcoins safely in a paper wallet, and around 305 mBTC of almost unspendable bitdust in my live wallet.
I mined about 1.4 mBTC, and all the rest came from free sites over the past year.
I've got 13.7 mNMC  from merged mining, and I've also mined just over 10 Freicoins, which are slowly evaporating!

1Le52kWoLz42fjfappoBmyg73oyvejKBR3

If I am chosen for a payment, then thank you.

Now that I have upgraded to version 0.8.5, do I still need the "checklevel=2" line in my bitcoin.conf file?
Is it now safe to comment out or remove this line, or was its inclusion intended to be permanent?

I encountered this problem this morning before I was aware of this thread, but in my case reindexing, although it took all day, was successful.
I have now added the suggested line to my bitcoin.conf file, and when I tried it again, it started up correctly.
Lowering the checklevel can't be good for security, so hopefully we will be informed when the extra line may no longer be needed?

I don't have any problem with the username and password for the pool I am using, I just have a problem figuring out the correct syntax to use with the -x option for the proxy server that that particular computer is using. The proxy username is PUBLIC\*****@LibraryPublic
So you are saying it should look like:
-x http://PUBLIC\*****@LibraryPublic@***.***.***.***:8082 ?

OK, thanks for your help, I'll try out that configuration tomorrow.
I'm not convinced that it will work though because my username also has an @ symbol in it.

I don't understand what you mean.
I have tried using  -x http://<proxy address>:8082:<user name> but this doesn't work.
I need to know the correct syntax to add the user name.

I am trying to use this software on a work computer that uses a proxy, so I have addded "-x http://<proxy address>:8082"
The output from the terminal says "[2013-07-02 10:17:04] HTTP request failed: The requested URL returned error: 407 Proxy Authentication Required"
The proxy needs me to add a user name, which I do know.
What is the correct format to add my user name to the proxy option to make it work?

OK, I've replaced the files  bitcoind and bitcoin-qt which were in /usr/bin with the new 0.8.3 versions, and it works.

Thanks for your advice, I should have known that the solution was that simple.
So it turned out I was getting a bit panicky for nothing!

I still think that 10.04  should be supported in the PPA  for a while longer.

I have noticed that 0.8.3 hasn't been released on the PPA for Lucid (10.04), which I am still using.

I know it's been a few weeks since Ubuntu stopped supporting 10.04 with updates, but I was hoping that my Bitcoin wallet software wouldn't be left out in the cold quite so soon!

And before anyone says it, I don't want to do a network upgrade to 12.04, I would rather do a clean installation, but I've got nowhere to store my 100GB+ of data while I am doing it, so I am putting off upgrading as long as I possibly can.

Please reconsider releasing 0.8.3 on the PPA for Lucid.

This Python program works great.
https://bitcointalk.org/index.php?topic=102740.0
You can use it to monitor the blockchain, and have fun watching how much people are spending, in real time.
It also tells you when a new block has been mined.
Is this what the OP was after?