c# - How to reslove the error of service -

i have .net project [scenario] in i:

1. downloaded files winscp.com library in .net 2. parsed them, created tokens, inserted them sql-db using linq sql. 

problem during converting service:

the downloading part goes fine when run service *********************************************************************** when pushing db using linq sql gives exception without entering single row in db 

i not know, why so. kindly me if 1 knows mistake being made me.

note:the exception found using eventlog under:

application: errlogsservice_57_92.exe  framework version: v4.0.30319 description: process terminated due unhandled exception. exception info:  system.data.sqlclient.sqlexception stack: @  system.data.linq.datacontext.submitchanges(system.data.linq.conflictmode) @  errlogsservice_57_92.errlogscreation.read_log_file(system.string, int32, int32) @  errlogsservice_57_92.errlogscreation.parsefileandpush(int32) @   system.threading.executioncontext.runinternal(system.threading.executioncontext, system.threading.contextcallback, system.object, boolean) @ system.threading.executioncontext.run(system.threading.executioncontext, system.threading.contextcallback, system.object, boolean) @ system.threading.executioncontext.run(system.threading.executioncontext, system.threading.contextcallback, system.object) @ system.threading.threadhelper.threadstart()  

the code inserting data is:

if (checklineerrornot(line_str_is)) {     sql_db_logs_adatacontext rowinsert = new sql_db_logs_adatacontext();     col1 = get1_column_datetime(line_str_is, 0);     col2 = get2_column_javafilename(line_str_is, 59);     col3 = get3_column_portnumber(line_str_is, 90);     col4 = get4_column_errorstring(line_str_is, endindexof_javafile, line_str_is.length);      // request creation insert error-logs     logserror insertqry = new logserror     {         datetime = col1.tostring(),         filename = col2.tostring(),         portnumber = col3.tostring(),         errorstring = col4.tostring(),         id_ip = (int)ip,         id_file = (int)id_file_is     };     rowinsert.logserrors.insertonsubmit(insertqry);     rowinsert.submitchanges(); } else {     ; }