You have to tell us a lot more if you want help. This bit could have been useful information:

>I have tried the connection string using firebird connection string builder
>User=SYSDBA;
>Password=masterkey;
>Database=SampleDatabase.fdb;
>DataSource=ip address of server;
>Port=3050;
>Dialect=3;
>Charset=NONE;
>Role=;
>Connection lifetime=15;
>Pooling=false;
>Packet Size=8192;
>ServerType=0;
>but above dint work
>then i tried this also
>but now success.....please, help
>User=SYSDBA;
>Password=masterkey;
>Database=ip address:C:\SampleDatabase.fdb;
>DataSource=ip address of server;
>Port=3050;
>Dialect=3;
>Charset=NONE;
>Role=;
>Connection lifetime=15;
>Pooling=false;
>Packet Size=8192;
>ServerType=0;

I think this seems to be quite OK (though I must admit that most of the entries I've no knowledge of), at least if your database is located at C:\SampleDatabase.fdb on the server. A more recommended way would be to have the database somewhere else on the server, register e.g
SampleDb = C:\<My>\<Database>\<Path>\SampleDatabase.fdb
in the Aliases file on the server and then use Database = SampleDb in your connection string from the client.

There can be lots of reasons for a database "not working", if you want helpful advice, you must provide a much clearer problem description (you've told us what you want to do, a tiny bit about what you've tried to do and nothing about how things haven't worked). It can be things internal to Firebird - e.g. the Firebird user not having enough rights on the server, DatabaseAccess being set to None or Restrict in firebird.conf (not the default setting, so unlikely), the Firebird server not running or external issues like anti-virus software blocking port 3050.

Can you at all connect to the database from the client? E.g. through IB_SQL, FlameRobin, IB Expert or Database Workbench? If you haven't tried, I suggest e.g. downloading the trial version of Database Workbench (written by Martijn) from http://www.upscene.com/downloads.php#dbw, register the database you want to connect to and see if you manage to connect and open a query. If you get an error message that you cannot get past, write it to this list.

HTH,
Set