QUOTE:
Did you try to import the content in your J1.5? Do you have the ???? issue?

I have installed it locally, transferred some data and all the characters look ok.

Try getting a copy of JoomlaPC which is what I'm using.
And installing the data that way we will be on the same page.

If you are still getting ??? it may be due to the operating system or a font that you need.
I'm using just the standard version of vista but have over time installed quite a few fonts.
What operating system are you using?

Ok, I found out the root of this issue. It's caused by simple script that installed Joomla. I manually installed it, and it's ok now.

By the way, if contents belong to different users, how to transfer that with contents.

Steve, thanks for your excellent help.

QUOTE:
Ok, I found out the root of this issue. It's caused by simple script that installed Joomla. I manually installed it, and it's ok now.

Glad to here you woked it out

QUOTE:
By the way, if contents belong to different users, how to transfer that with contents.

When someone adds content it is assigned to them via their membership ID.
So when moving content to another site the member or members that added the content may not have the same ID, that's if they are even a member of the destination site.

To try to take as much info as possible when "Export Content" compiles articles it will grab the authors alias assigned to each article and will transfer that over to the destination site.

If you want to keep a site the same across the board you would need to move the entire site all at once to keep all the ID's in sync.

QUOTE:
Steve, thanks for your excellent help.

Glad to help

QUOTE:
To try to take as much info as possible when "Export Content" compiles articles it will grab the authors alias assigned to each article and will transfer that over to the destination site.

If you want to keep a site the same across the board you would need to move the entire site all at once to keep all the ID's in sync.

Sorry, I don't quite get what exactly I need to do here. What are the steps I need to do so that contents will be transfered with related member ID?

You could hack export content to move the id's but it want do you much good unless you move the entire site in one go.
Otherwise the user id's won't match up to the content items.

Also I don't think passwords are handled the same on 1.0+ and 1.5+ so if you want to move the members there are a few changes that are needed and there is a lot more to it than just moving the user table.

If you want everthing the same on both sites you might be better off using something like:

http://extensions.joomla.org/component/option,com_mtree/task,viewlink/ link_id,3895/Itemid,35/

Which will move the whole site.

I also just noticed this which has only just been released that might be handy.
http://extensions.joomla.org/component/option,com_mtree/task,viewlink/ link_id,5430/Itemid,35/