For database connection error issue : 

1. First check whether database is started or not in server system . If not, then start the database server.

2. Then go to Google Chrome , in the address bar type http://172.19.64.105:8080/POS , Press Enter .

3. Click on "Database_build", then click on pmt.zip 
4. Now pmt.zip file (4MB) will be downloaded , after completion of downloading, open that downloaded folder & unzip that .

5. Go to that PMT folder & double click on start file ; one small window will be open.. 

6. In that PMT window , give the server system IP address & browse the location as desktop and then click on "Generate" ..

7. Then po_connection.db file will be generated in desktop ... Copy that file & paste it in below two paths : 

C:/POS/APPLICATION/BO/BUILD/DB_CON 

C:/POS/APPLICATION/COUNTER/BUILD/DB_CON 

then open the back office & counter application....