i was wondering what applications would be more suitable for assem. language instead of C with an application example.

Here are some references for you:

AVR libc

Programming in assembler for starters

There are many more on the web, search on "AVR Assembler".

I am not really sure what you mean by "more suitable"?

But...

Software Applications that are more likely to need Assembly Language Programming are going to be applications that:

 1  -  Need to have the fastest execution possible  
 2  -  Need to have as much functionality that will fit into the MCU's Flash as possible

I, personally, am not that fond of Atmel's choices of mnemonics and structure of their Assembly Language. I find that it doesn't flow very well in my thought process.

That being said, there are times where it is helpful/necessary to be used but that is not all that often.

More-often-than-not Assembly Language is mostly used to "augment" specific portions
of an Software Application in order to make that specific portion/element more
efficient. Usually that would be involved in handling high numbers of Interrupts. (In my experience.)

There is not really much need to program an entire Software Application in Assembly
Language.

There is, however; also just "pure passion"...

(Software Applications/Functions that come to mind that "could" benefit from the
"Fastest Execution Possible" may be Emulating a Processor in Software, MP3/WAV File
Decoding, USB Interface with high speed data collection, Decoding a video file,
decoding a jpg... All, but the first two of these, are very "iffy" if they are truly
practical.)

i was trying to program my microcontroller and had the following error on my prolific usb com port "Windows cannot determine the settings for this device. Consult the documentation that came with this device and use the Resource tab to set the configuration. (Code 34)". i tried everything but cannot get it to work. my computer is a lenovo G560 series. i cant find any documentation on how to manually change settings.