Arch Linux

Description:
I have set /etc/wvdial.conf Defaults dialer according to my network provider(BSNL) and phone specifications. My phone is Nokia XpressMusic 5130-classic. About a year ago, with the same configuration, it was working fine. The phone works fine on a Windows 7 system and a Gentoo system with the same configuration file. On Archlinux, however, I get the following when I give the command wvdial:

--> WvDial: Internet dialer version 1.61
--> Cannot open /dev/ttyACM0: Device or resource busy
--> Cannot open /dev/ttyACM0: Device or resource busy
--> Cannot open /dev/ttyACM0: Device or resource busy

The output of lsusb is as follows:
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 002: ID 0421:0208 Nokia Mobile Phones

Additional info:
* package version(s)
kernel-2.6.39

* config and/or log files etc.
/etc/wvdial.conf is as follows:

[Dialer Defaults]
Init1 = ATZ
Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
Init3 = AT+CGDCONT=1,"IP","bsnlnet"
Password = <password>
Check Def Route = 1
Phone = *99***1#
New PPPD = 1
Modem Type = USB Modem
Stupid Mode = 1
Baud = 460800
Auto DNS = 1
Dial Command = ATD
Modem = /dev/ttyACM0
ISDN = 0
Username = <username>